【Abstract】 During two consecutive mating seasons from August 2001 to December 2002,we observed the sexual behavior of Sichuan golden monkeys in the Chengdu Zoo and the Shanghai Wild Animal Park. We collected urine samples from females in the early morning. We also measured urinary estradiol and progesterone levels using radioimmunoassay. Based on the estradiol concentration during the menstrual cycle, we discovered that the length of the menstrual cycle was 286 33±1 67 days. The length of pregnancy was about 200 days. The level of estradiol after impregnation was significantly different with the level during the same period in the non receptive part of the cycle. Thus we could diagnose early pregnancy in female Sichuan golden monkeys by checking their urinary estradiol level .更多还原