Abstract: The farmland rats Rattus rattoides eziguus were fed in 1990-1992.Male and female adultswere stimulated into oestrus artificially, urge ovulation and fed in pair.The female ones were dissected periodically after pregnancy.the length and weight of embryos were determined.Accordingto the figures between the embryos age and embryos lenght.and between the age with the weight.the regressive analysis was made by linear or quadratic function to establish a mathematical modelfor predicting the peak stage of the furrowing of farmland rat.Simultaneously.the peak stage ofyoung mouse population and the occurrence of heavy eating period can be predicted based on thedifferent periods of individual development.The prediction of furrowing peak stage of farmland ratin Spring and Autumn 1993 was identical to the field examination by digging rat holes and catchingrats.