Abstract: Smoothed particle hydrodynamics (SPH) is a typical meshless particle method. However, the heat flux boundary of laser radiation in SPH method is a big problem which dues to the difficulty of determining particles which receive the lasers energy in a time-step. In this paper, the problem is solved by the difference method, and a three-dimensional program LAMP (laser ablation material program) is compiled with FORTRAN language to numerical simulate the interaction between 5.0109 W/cm2 continuous wave laser and a columnar aluminum target. The boundary particles which receive the lasers energy are accurately determined, and temperature distributions at different time in the target are obtained.