肾盂输尿管连接处（PUJ）梗阻为原发性肾积水最常见的原因，约占50％左右，在儿童尤其如此。导致PUJ梗阻的病因很多，多为先天性。因所致肾积水多为巨大型，肾功能有不同程度的损伤，加之对本症认识不足。检查方法选择不当，常在引起并发症后才被发现，故术前诊断准确率不高。 PUJ obstruction is the most common cause of primary hydronephrosis, accounting for about 50%, especially in children. PUJ cause many causes of obstruction, mostly congenital. Due to the vast majority of hydronephrosis, renal function have varying degrees of injury, coupled with lack of knowledge of the disease. Improper selection of inspection methods, often caused by complications were found, so the accuracy of preoperative diagnosis is not high.