In some male infertility patients, after the semen routine and morphological examination, the doctor reads the report of the semen routine and morphological examination and orders the patient to undergo further examination for seminal plasma biochemistry. Some patients wonder why they need to do seminal plasma biochemistry. The semen can be divided into two parts just like the fish and water in a pond, one of which is 5% of the formed component: sperm and the other is 95% of the invisible component called seminal plasma, of which the seminal vesicle gland fluid accounts for 60%, the prostate gland fluid accounts for 30%, and the urethral bulb gland and urethral gland fluid accounts for the remaining 5%. The number and viability of spermatozoa in seminal plasma biochemistry are closely related to the biochemical composition, biochemical properties, and pH value of seminal plasma. The measurement of seminal plasma biochemical indexes is important for the treatment of male infertility. Zinc ions of seminal plasma can bind to proteins and distribute on the surface of spermatozoa to protect biological membranes, which helps to delay lipid peroxidation of membranes and maintain sperm vitality. In addition, zinc has a stabilizing effect on sperm nuclear chromosomes. Chronic zinc deficiency can lead to gonadal hypoplasia, hypogonadism, and decreased sperm motility and sperm density. The number of leukocytes in the seminal plasma is usually used as an indicator of accessory gonadal infections such as prostatitis, seminal vesiculitis, epididymitis, etc.. The large number of leukocytes infiltrating the epithelium of the epididymis and prostate causes dysfunction of the accessory gland, which may disrupt the balance between coagulation factors originating from the seminal vesicles and liquefaction factors from the prostate, resulting in abnormal liquefaction performance. Abnormal liquefaction in turn affects the viscosity of semen, which increases and prolongs liquefaction time. The biggest disadvantage of computer-assisted semen routine is that it cannot distinguish between young white blood cells and daisy sperm, which causes infertility in some cases with normal semen routine. Because a large amount of WBC in semen can inhibit the viability of sperm, unexplained weak spermatozoa should exclude the effect of WBC. In addition, it can be used as an efficacy observation indicator for some patients with inflammatory infertility to clarify the effect of antibacterial and anti-inflammatory treatment. Seminal plasma elastase is another indicator of male reproductive tract infection. It is an enzyme that can hydrolyze elastin in the body and is distributed in a variety of tissues and cells such as neutrophils and macrophages. When the reproductive tract is infected, there is an increase in neutrophils in the seminal plasma and subsequently an increase in the amount of elastase secreted extracellularly, which, together with other oxidizing substances, exerts a local anti-inflammatory effect. Seminal plasma elastase can be used as a diagnostic and prognostic test for quiescent reproductive tract infections, and it has important clinical significance in the assessment of male fertility, the diagnosis and treatment of male infertility, and sperm function. Citric acid is the main secretion product of the prostate gland, which has the ability to nourish sperm, participate in the liquefaction process of semen, keep the osmotic pressure of semen in balance, maintain the proper pH to ensure a normal environment for sperm survival, and play an important role in sperm vitality. Citric acid is an important indicator to determine the state of androgen secretion and to evaluate the function of the prostate. Acid phosphatase is a glycoprotein secreted by prostate cells, which is an important indicator of prostate function. The acid phosphatase content decreases in prostatitis, and the seminal plasma acid phosphatase content decreases significantly in abnormal semen liquefaction. The acid phosphatase content increases in the case of prostate hypertrophy or early prostate malignancy. Fructose, which is the main energy substance of sperm, is examined by seminal plasma biochemistry. When the seminal vesicle gland is dysfunctional, it inevitably leads to a decrease in the total amount of semen, as well as a decrease in the fructose content within the semen, and low fructose in turn causes a lack of sperm vitality, leading to infertility. In addition, the fructose content is clinically measured in patients with azoospermia to determine whether the seminal vesicle gland is congenitally underdeveloped or underdeveloped. Anti-sperm antibodies are caused by the destruction of the normal blood-testis barrier, resulting in the production of anti-sperm antibodies and immune infertility. They can be found in both seminal plasma and serum, and are of greater clinical significance when present in seminal plasma biochemistry. This index should be reviewed for some patients with normal semen routine, and also for some unexplained weak spermatozoa to rule out immune infertility. Finally, the use of seminal plasma biochemistry avoids some invasive tests. For example, for the diagnosis of obstructive azoospermia, vasectomy was used in the past, but this test is costly, damaging, and prone to produce anti-sperm antibodies, and it cannot help for obstruction of the epididymal segment. The use of seminal plasma biochemistry is less expensive, non-invasive and covers the entire seminal tract. Neutral a-glucosidase, produced mainly by the epididymis, is a specific and marker enzyme of the epididymis and is a functional indicator of the epididymis. This enzyme is important for certain infertility conditions related to the epididymis. For example, obstructive azoospermia, it has a definite diagnostic value. It is decisive for differentiating obstructive lesions of the vas deferens from azoospermia due to testicular spermatogenesis disorders.