Striped Field Mouse (Apodemus agrarius) distributes in Guizhou Province broadly, which is one of the key pest rodents in farmland. To better understand reproduction characteristics of the Striped Field Mouse population in Guizhou Province, we monitored the mouse populations in Yuqing, Xifeng, Cengong, Kaili, Leishan, Duyun, Wengan, Dafang counties from 1984 to 2014 (Table 1), assessed the reproduction parameters including sex ratio, pregnant rate of females, average fetuses and percent of males with prominent testicle, and analyzed the pattern of monthly variation of Striped Field Mouse in Guizhou. We totally trapped 20 113 mouse and made observation. There were no differences in the reproduction index between geographical populations except for average fetuses (Table 2). A two-peak type of breeding season was revealed by the monthly variation of female pregnant rate and percent of males with prominent testicle (Fig. 4). The highest proportion of pregant females occurred in spring (from April to May) and in the end of summer to beginning of autumn (from August to September) (Fig. 3). The litter sizes varied from 2 to 10, with common size of 4 to 7 (Fig. 5). The average litter size varied monthly (Fig. 6). Generally, pregnant females were present at two peaks, one in spring and one in autumn. The proportion of pregant femaled was lowest in winter (from December to February of next year). The population abundance reached the peak in June (Fig. 1).