To mitigate the social status of the decreasing total fertility rate, the central Taiwan government promote child births by means of a variety of policies, including social insurance, maternity benefits, parental leave allowance, special tax deduction for preschool children, etc. Local governments, however, have provided one-time- allowance to boost the dropping birth numbers in their jurisdictional area. In past studies, the effectiveness between total fertility rate and the maternity allowance in the form of cash by local governments has less been studied. Most studies focus on the factors which affecting the low fertility rate. This study examines the correlation between total fertility rate and the amount of cash maternity allowance by comparative method. Using data from 20 jurisdictional area of Taiwan, this study investigates the impact of maternity allowance by comparing different regions as well as different periods of time. The biggest problems in the course of the study were “threats of internal validity” and ”the cases already affected by independent variables”. The results suggest that the more the cash maternity allowance provided, the more obvious the policy effect becomes only when the allowance exceeds $20,000, any allowance less than $20,000 has only symbolic meaning. Moreover, the fertility rate has neighborhood effects, in addition to the policy based on economic incentives, the government should provide other measurements to boost birth rate.