Abstract: To study the histopathological changes in spontaneous kidney lesions of breeding maca-ca mulatta,kidney samples from the monkey at the age of 2～20 years were investigated by routine histological technique.The results showed that various spontaneous lesions including glomerulus’s，renal tubules and interrenal tissue etc, totaling more than 14 kinds in different degrees ,were found in 79. 4% of the monkeys. The degree and the frequency of the lesions were increased with age. The results suggested that the spontaneous lesions of kidney were often ob-served in macaca mulatta and its interference effect on medicine research should be considered se-riously.