The decomposition of TiH2 at high temperature was studied, and it was applied in the manufacture of high purity WTi alloy. The effect of hot pressing sintering process on the purity of WTi10 speicmen was investigaed. Microstructures by different raw material ratios were investigated, too. Optical microscope, Scanning electron microscope (SEM), CS analyzer, ONH analyzer and Glow discharge mass spectrometry (GDMS) were used to analyze the microstructure and impurities of the WTi10 specimens. The results indicate that with the increase of the ratio of TiH2 to Ti, the lower impurity of C,S,O,N,H more uniform distributed microstructure, and much less diffusion of W to Ti matrix. The purity of WTi10 products is up to 99.9993%.