Abstract: A diploid cell strain (KIZ-7901) of red muntjac (Muntiacus muntjak) has been established in our laboratory.The diploid chromosome number of red muntjac (♂=7,♀=6) is the lowest among all vertebrates,so it is a good assay system for the testing of chemical mutagens.We use N,N-methylene-bis (2-amino-1,3,4-thiadiazole) as the chemical muntagen.The experimental results show that the greater the dosag eof this chemicaluses and the longer the duration of the treatmentlasts,the greater the rates of the sister chromatid exchanges (SCEs) are,especially the frequencies of chromosome aberrations.