Abstract: The effect of various Pre-HIP heat treatments on the size and distribution of Prior Particle Boundary(PPB) carbide precipitaties, γ' volume fraction and grain size of HIP billets of Rene'95 P/M alloy has been studied. And the possibility of the elimitation of PPB carbide segregation by using Pre-HIP heat treatment has been explored. The results show that Pre-HIP heat treatment can reduce the degree of PPB carbide segregation, increase the γ' volume fraction, but leave the grain size unchanged. This is mainly due to the improvement of Pre-HIP powder surface state, and precipitating environment of carbides on PPB.