The influence of element addition ways on the microstructure and the performance of P/M Ti-6Al-3Nb-2Zr-1Mo alloy (Ti80) was investigated in order to improve the processing properties. The results indicate that Al must be added by NbAl, ZrAl, MoAl or MoAlTi pre-alloy to obtain the relative density above 97%; Nb and Zr can be added by elementary substance or pre-alloy; Mo should be added by MoAl or MoTiAl pre-alloy. Ti can not completely added by TiH2 powder. The tensile fracture of P/M Ti80 alloy exhibits outstretch rupture and has no crack when Ti is added by Ti powder while the tensile fracture shows brittle rupture and has distinct cracks when Ti is added by TiH2 powder. Hydrogen is the main reason causing cracks of the alloy. Adopting appropriate element addition ways, good performance of the P/M Ti80 alloy can be obtained, such as σb=890-1020 MPa, σ0.1=755-875 MPa, σ0.2=785-895 MPa, δ5=5.5%-9.0%, and ψ=11%-20%. Compared with the forged alloy, the sintered alloy has much higher intensity and lower plasticity.