Pure molybdenum powder was successfully directly compacted into the dense body material by high-pressure torsion at 350℃. The effects of HPT on pore closure and performance strengthening of the powder particle were investigated by optical telescope, microhardness-testing device, scanning electronic telescope and X-ray diffractometer. The results indicate that the molybdenum powder mechanical mesh each other by particles movement and deformation under shear force, at this time the interface bonding performance, the large chain pores in particles were welded effectively after high-pressure torsion. In the HPT process the crystal size decrease from 59.8nm to 46.9nm, the micro strain increases from 1.04′10_-4to 1.12′10_-3. The lattice defects caused by grain refinement and micro strain can promote dislocation multiplication and tangling to strengthen the matrixmethod.