The main purpose of this paper is to introduce a new historical demographic database for Tamsui studies and presents it application. Since 1989, Prof. Arthur P. Wolf and Ying-Chang Chuang have starting to digitize household registers and publish a series of research results. Tamsui was an important harbor during colonial period and has rich humanities, customs and habits. Tamsui household registers had not been digitized until this project in 2014. We find many differences between Taipei and Tamsui, and one of the interesting results is that Tamsui men and women had higher death probabilities than Taipei men and women before age 35. After age 35, Tamsui men and women had lower death probabilities. This argument provides two ways thinking: biological theory (Darwin's theory of evolution) and environment ecology. It is worthy for further research, when we face the issue of an ageing society