Global climate change affects the relationship between climate factors and rodent population dynamics, which is becoming a hot issue in rodent control research. Population dynamics of Apodemus agrarius in Chang An District, Xi'an, were monitored using the live capture method to elucidate the patterns of change in rodent population dynamics. Generalized additive models were used to analyze the nonlinear relationship between the rodent population density and climate factors in the respective region from 2015 to 2018. The results showed that the total number of Apodemus agrarius population showed a trend of decline. The model results indicated that Apodemus agrarius population density further presented a statistically-significant positive self-regulation effect (F_{1.00, 5.77}=27.062, P<0.01). The rodent density of each month was mainly affected by that of the preceding month. The monthly average temperature affected rodent density, showing a clear bell-shape (F_{1.90, 5.77}=4.696, P<0.05), and positive and negative association at temperatures below and above 21 ℃, respectively. The monthly total precipitation also affected the rodent density, showing a clear bell-shape (F_{1.87, 5.77}=3.879, P<0.05), and negative and positive association with rodent density at precipitation levels above and below 90 mm, respectively. Therefore, temperature and precipitation influenced rodent population dynamics. Low temperature and drought or high temperature and abundant rainfall conditions were not suitable for rodent reproduction and growth.