Objective To analysis for the characteristic and significance of the ultrasound diagnosis of varicocele in children.Methods 19 children with primary varicocele patients were conducted bilateral spermatic vein and left renal vein ultrasonography,a comparative analysis was performed for other side varicose,diameters and the compilications of nutcracker phenomenon.Results Among 19 with varicocele,18 were found in the left side,1 case in the bilateral.Spermatic vein diameters were 2.2~3.4mm,the average of which was 2.7±0.4.All cases were complicated with nutcracker phenomenon.Conclusions The cause of varicocele children is mainly due to nutcracker phenomenon,which should be regarded as the routine inspection of renal vein and for which the treatment is done.Nutcracker phenomenon should be used as the census for children Varicocele.