The left varicocele internal diameter of 2.7 millimeters is not normal and is considered to be a varicocele I degree, which is a vascular lesion. Normally, the internal diameter of varicocele should not be more than 2 millimeters, so, 2.7 millimeters internal diameter of left varicocele is abnormal. Moreover, according to the grading of varicocele, the internal diameter of varicocele of 2.2~2.7 millimeters belongs to degree I. Therefore, the internal diameter of varicocele of 2.7 millimeters on the left side belongs to degree I of varicocele. Varicocele belongs to a kind of vascular lesion, which has been shown to be mainly related to venous valve insufficiency and venous return obstacle, including congenital dysplasia, few elastic fibers within the vein wall, hydronephrosis, and so on. Most patients are asymptomatic, while some patients experience symptoms such as enlargement of the affected scrotum, vague pain, and swelling. Patients with left-sided varicocele with an internal diameter of 2.7 millimeters need to go to the hospital in time, cooperate with the doctor to carry out standardized treatment, the general prognosis is better, so as not to delay the treatment.