The toxicological tests of the Yangtze River source of drinking water on the reproductive system of male mice (Mus musculus) were conducted in order to protect human and environmental health. The mice were fed with the source water for 90-day and their body weights and relative organ weights were not significantly altered. The results of flow cytometry analysis showed that the relative percentage of the primary spermatocytes (4C) increased significantly, however, significant depletion was observed in the relative percentage of elongated spermatid (HC). These alterations in different germ cell populations were reflected in the various germ cell ratios. The ratio of 1C:4C showed declines while the ratio of 4C:2C increased and the percentage of abnormal sperm increased significantly. There were obvious testicular histopathology distinguishes observed in expansion of interstitial space and reduction in the number and size of Leydig cells. The data demonstrated that the source of drinking water from Yangtze River had actual toxicity on male mice reproductive system and suggested that the source water pollution should be controlled for protection of human health.