The whole ablation process of target heated by pulsed lasers is studied in this paper. Under the appropriate dynamic boundary conditions, have been investigated in detail the heat flow equation with heat generation term, and the temperature distribution of target before and after the melting. In particular, after target melting, the temperature distribution and the interface position between the solid and liquid phases as functions of time are presented in the solution of analytical expressions. Additionally, under the energy balance conditions, the dependence of the ablating surface position on the time is investigated. Consequently, the ablation of target Si has been calculated. This research shows a positive result compared with the relevant experiments.