According to statistics by the Council of Taiwan, the fertility rate in Taiwan is the world's lowest in 2010. The average number of babies born to women of childbearing age life is 0.9 people. In other words, the average number of children per woman is less than 1. In 2023 Taiwan will enter a negative population growth. Taiwan's population structure becomes a declining birthrate, aging society.The future workforce reduction will greatly affect the competitiveness of Taiwan. The most important factor of decreasing fertility in Taiwan is economics.The majority of people think that raising children has become a heavy burden.Except for a few women, due to personal career planning, work and other factors not yet fertility or infertility .The majority of women still want to have her own children.The most people's attitude of giving birth is reserved because of high unemployment rate ,unsound preschool education system and little child-care subsidy . In the empirical study found that there is no relationship between the fertility rates and the amount of maternity allowance.That is maternity grant can not increase fertility rate. If maternity benefits can not be improved the fertility rate,the fertility incentives of tax breaks are smaller to people.There are some shortcomings of tax incentives for increase the birth,such as revenue loss,tax fairness and so on. It is also possible to increase the birth rate had no significant improvement. The government uses tax benefits to increase fertility rate depending on revenue loss and population growth . The amount and range of tax incentives should be calculated carefully in order to make a balance between the revenue loss and population growth.