Abstract: According to the variation of pregnancy rate,different types of placental scar rate and juvenile rate,we developed a method to estimate the reproductive parameters of rodents such as reproductive delay (the average time for littered female to litter again),juvenile maturing time (the average time for juvenile to litter after born),reproductive deviation and so on.The estimation results about C.triton in Raoyang county of Hebei,China in 1986 are as follows:During the breeding seasons from March to September,the overwintered females,juveniles in April and May,juveniles in June and July,and juveniles in September litter respectively 3,2,1,and o times.The first littering pattern of overwintered females is a normal distribution,the average date of littering is April 20 and standard deviation is 13.4 days,The litter size is 9.1260(±2.5971).The sex ratio (female:male) is 1∶1.4926.The reproductive delay is 59 days.The juvenile maturing time is 62 days.The average time for juvenile to be trapped by wooden traps is 24 days.