Age-specific fertility rate and total fertility rate of females are the most important parameters in population dynamics. This paper proposes an algorithm to get these parameters from the initial age distribution and the total population the years followed. The idea is natural in the sense that the total population is easily to be obtained in a closed society. The authors use a discrete population model to formulate this problem into an inverse problem, which is ill-posed generally. A necessary and sufficient condition for the identifiability is established. An algorithm for reconstruction of age-specific fertility rate is developed.