The invention discloses a process of using a powder metallurgy method to prepare alloy, comprising the following steps: 1. master alloy is synthesized at high temperature; 2. the high energy ball milling and thinning are carried out on master alloy powder to obtain master alloy superfine powder with the average particle size of 1-1.5Mum; 3. the star-type material mixing is carried out; 4. the cold isostatic compaction is carried out: mixed powder after the star-type material mixing is filled in a square isostatic compaction sheath for the isostatic compaction sheath to obtain powder compact; 5. lower temperature diffusion sintering is carried out: the powder compact is put in a vacuum furnace for the diffusion sintering to obtain an alloy sintering billet with uniform composition; 6. subsequent treatment: the conventional subsequent treatment is carried out on the obtained alloy sintering billet to obtain the finished product. With reasonable design, the processing of using the powder metallurgy method to prepare alloy can effectively make up the composition segregation generating deficiency of a conventional melting method for preparing alloys with large differences of melting point, density and mass ratio, realize the uniform distribution of components in the alloy and effectively ensure various properties of the prepared alloy.