One big testicle and one small testicle without pain, it is recommended to go to the hospital for examination to clarify the possible causes, the specific causes are as follows: 1, varicocele, usually occurring on the left side, there will be left testicular atrophy phenomenon, the texture of the testicle softened by touching with the hand, but there is no obvious pain, but also in the scrotum can be touched to the varicocele of the blood vessel tissues, you need to carry out ultrasound examination of the scrotum to further clarify the 2. Epididymal tuberculosis, when there is chronic tuberculosis of epididymis, the volume of testis on the diseased side can be increased, and at the same time, the texture of testis and epididymis can be hardened, which needs further tuberculin test and scrotal ultrasound examination for further clarification. 3. Testicular tumors, the volume of testis on the side of the tumor is gradually increased and hardened, which is usually not accompanied by obvious pain, but when the volume of the tumor increases to a certain extent, it can be manifested as softness of scrotum and hardness of the epididymis, which is not accompanied with obvious pain. However, when the tumor volume increases to a certain degree, it can be manifested as swelling sensation in the scrotum, which requires further testicular tumor index test and scrotal ultrasound, CT and other examinations to further clarify whether there is testicular tumor.