Abstract: The population dynamics of striped hamster (Cricetulus barabensis) has been studied in Huhehot district from March to November 1984-1989.A total number of 2920 specimens were collected,among which 1675 are males and 1245 are females.The results are as follows:The peaks of seasonal numbers of striped hamster in fluctuation curve varies from year to year.There are two peaks,the peak in the rear is higher than the one in front.Taking height of the grinding surface of the posterior molar and the molar wear as the age criteria,the samples were divided into four age groups.There are not old groups in Huhehot district.There are seasonal and annual changes in population age composition of striped hamster.The sex ratio of all the specimens proves that the male accounts for a larger proportion than the females,and such is the case in the adult group,but females aremore than males in young and subadult groups.The reproductive periods of males are 9 months.The beginning of the females breeding period varies with years.In 1985 and 1987-1989 it began in March and in 1986 it started in April.Females stop breeding from Oct.to next Feb.and they have two breeding peaks in a year.The first peak was between spring and summer and the second was between summer and autumn.Young striped hamster became matured within 2-3 months and adults breed 2 times each year.An annual average litter size of female was 6.19±0.08 in 1984-1989.