W skeleton with high strength (347.8±10.6 Mpa(1450℃), 407.4±14.2 Mpa(1500℃), 543.9±8.7 Mpa(1550℃) and hierarchical pores structure (3-10 m\200-500 nm) was prepared by SPS at different sintering temperatures (1450℃, 1500℃, 1550℃) and at axial constant pressure (40Mpa) for 5 minutes by using the particle size distribution of 15-106 m porous spherical agglomerate W powder as raw material. The densification behavior, microstructure changes and mechanical properties of SPS sintering process were systematically studied by XRD、SEM and universal testing machine. The results show that SPS can produce W skeleton have developed sintered neck and hierarchical pores structure with no significant change in phase before and after sintering and porosity of 30%-40%. The sintering densification process of W skeleton with hierarchical pores structure by SPS can be divided into four stages: the first stage is the pressure increase stage, the relative density of sintered sample increases rapidly with the increase of pressure; the second stage is a typical particle rearrangement stage; the third stage is a typical sintering metaphase, the relative density of sintered sample increases with the increase of temperature, when temperature higher than 1000℃; the fourth stage is the end of sintering, and the densification degree is further improved due to high temperature creep inside the sintered body. The densification mechanism of the porous spherical W powder was determined as Pure diffusion densification by using the high temperature creep model, and further determined volume diffusion as the main mechanism and grain boundary diffusion as the auxiliary mechanism by the neck length equation.