Abstract: Weldability of PM-TZM molybdenum alloy using electron beam welding (EBW) was investigated in this study. EBW experiments on PM-TZM plates were carried out and microstructure and mechanical properties of the welded joints were analyzed. The results showed that the cross section of the weld zone (WZ) had a nail-like shape with the welding pores distributed along the fusion line. The WZ was composed of the coarsened equiaxed grains and columnar grains. The grains in heat affected zone were coarser than those in matrix area. Microhardness of joint presented an uneven distribution where the microhardness of the WZ was at the same level compared with the BM and the HAZ had the lowest microhardness. The tensile strength of the joint reduced sharply after welding compared to the BM that the room temperature tensile strength of the joint was 378 MPa which was 47% of BM. Tensile strength of the joint performed at 1 000 ℃ was 168 MPa. The tensile test fracture located at WZ and the weld fracture presented characteristics of cleavage fracture.