Varicocele can cause pathological changes in the testes that affect sperm production, resulting in decreased sperm motility, morphological immaturity of sperm cells and an increased number of acromegalic sperm. It has been found to be associated with the following factors: blood retention in the varicose veins, which affects sperm production by increasing the local temperature of the testes. Blood stagnation affects the blood circulation to the testes, which affects sperm production because the testes lack the necessary nutrient supply and oxygenation. The reversal of blood flow in the left internal spermatic vein brings metabolites secreted by the adrenal glands and kidneys, such as steroids, catecholamines and 5-hydroxytryptamine, to the testes. Steroids can inhibit spermatogenesis, catecholamines can cause chronic toxicity in the testes, and 5-hydroxytryptamine can cause vasoconstriction and premature shedding of immature sperm, causing male infertility. These factors can also affect the endocrine function of the testicular mesenchyme and interfere with spermatogenesis. Varicocele on the left side can also affect the right testicular function. There is a rich anastomosis of testicular veins on both sides, and toxins in the blood of the left side can go to the right side and affect the sperm production of the right testicle.