Visual observation of semen mainly includes the following aspects: 1. Appearance: normal semen just ejaculated out of the body is off-white or milky white, jelly-like, and semen that has not been ejaculated for a long time is light yellow. After liquefaction, semen is translucent and milky white. If semen is red, it is abnormal and there may be inflammation of the reproductive system, tuberculosis, tumors and other possibilities. 2. Volume: A normal male ejaculate volume is 2-6ml. If the semen volume is less than 1ml, the semen volume is reduced. If there is a persistent decrease in semen volume, along with the presence of sperm and pre-seminal cells, it may be hypogonadism caused by hypopituitarism. In addition, inflammation of the accessory glands may also lead to hypogonadism. Excessive semen volume can be seen in hypothalamic-pituitary gonadotropin hypersecretion. If the semen is liquefied or semi-liquefied, it may be azoospermia; if the semen liquefaction time is prolonged or even exceeds 1 hour, it is not liquefied. If the semen is not liquefied, it is mostly seen in prostatitis. 4. Viscosity: The main purpose of measuring the viscosity of semen is to understand the secretion of the accessory gonads. After the semen is completely liquefied, the semen viscosity is detected using the syringe needle suspension method and the glass suspension method. Normal specimens can form discontinuous hanging drops, and the length of mucus filaments usually does not exceed 2cm. High viscosity is often accompanied by semen non-liquefaction. 5. pH: PH test paper is used to determine the PH value of semen. Normal semen is mainly composed of alkaline seminal vesicle fluid and acidic prostatic fluid, with a PH value between 7.2 and 7.8. It is usually measured after the semen is liquefied. A prolonged delay may result in a decrease in the PH value. A change in the PH value of semen can affect sperm survival, metabolism and viability. high PH value is seen in acute inflammation of the seminal vesicle gland, prostate gland and epididymis, while a decrease in PH value can be seen in chronic infections of the reproductive tract.