Effects of vacuum heat treatment on microstructure and mechanical properties of extruded rods of 93W-Ni-Fe alloy sintered by microwave were studied. Fracture morphology and microstructure were observed by SEM and optical microscope, respectively. Quantitative analysis of each element of the samples before and after vacuum heat treatment was performed by energy spectrum analyzer. Relative density, tensile strength, elongation and hardness of samples were measured. The results show that the mechanical properties of the tungsten-based alloy are increased after vacuum heat treatment. Tensile strength and elongation are improved markedly, which are increased from 920 MPa to 988 MPa and from 9.7% to 18.6%, respectively. After vacuum heat treatment connectivity of tungsten grains is reduced, and transgranular cleavage fracture of tungsten grains and ductile tearing of binding phase are increased evidently. The content of tungsten element in binding phase is obviously reduced after vacuum heat treatment.