Body weight, weight of internal organs, and reproductive ability of conventional KM micewas studied. The results demonstrated that the average product number of mice was 13. 72 at onelitter, the average weight of mice was 1. 89 grams at birth, and the survival rate of sucking micewas 98. 41 %. The KM mice during the first 2 weeks after birth grew rapidly, it increased 0. 665grams a doy. From the second to the sixth week, the male and female mice increased 0. 7 and 0.55 grams respectively. From the seventh to the tenth week, the male and female mice increased0. 38 and 0. 32 grams respectively. The average number of days between litters were 23. 33.