Testicular size on one side and small on the other side is considered to be normal physiological phenomenon, but also considered to be related to pathological factors such as testicular tumor, testicular syringomyelia, etc., which can be treated with medication and surgery in conjunction with the cause of the disease. 1. Physiological reasons: Generally speaking, there is a slight difference in the size of testicles between two sides, one side is big and the other side is small, which is a normal physiological phenomenon and does not need special treatment. 2. Testicular tumor: the most common solid tumor in young and middle-aged men, which is related to cryptorchidism, Crohn’s sign and other diseases, and will lead to the situation of testicles being big on one side and small on the other. Treatment is mainly surgical resection with radiotherapy. It includes radical surgery, partial resection with preservation of testis, combined with chemotherapeutic drugs such as cisplatin, Vincristine, Bleomycin, and Gentamycin. 3. Testicular syringomyelia: caused by inflammation or surgical trauma to the testis and its nearby tissues, and caused by diseases such as chronic inflammation of the syrinx, which will lead to the appearance of testis on one side of the large and small. Antibiotic drugs such as cefdinir and levofloxacin are given to those with accompanying infections, and testicular syringomyelia reversal, or testicular syringomyelia resection, etc., can be chosen for more fluid accumulation. The above drugs should be used under the guidance of the doctor, do not use drugs on your own but lead to aggravation of the condition. There are more reasons for testicles to be different in size, and the treatment methods are also different. It is recommended to go to a regular hospital in time and follow the doctor’s instructions for standardized treatment.