Abstract: In order to improve the relative density of parts made of selective laser sintering (SLS), cold isostatic pressing (CIP) was carried out for densification. Numerical simulations of CIP SLS parts were made based on Drucker-Prager-cap model. Theoretical analysis and experimental verification were conducted based on simulation results. The results show the relative density of SLS parts was enhanced obviously. The contraction of the parts was uniform. The errors between experimental results and wanted dimensions of main dimensions were within 0.41mm, which indicated the simulation results accorded with the experiment results. The post-process of CIP SLS parts develops the application field of powder laser rapid prototype that lays the technical and experimental foundation for engineering practice.