The Ti-1Al-8V-5Fe （Ti-185） alloys were prepared by powder metallurgy process based on TiH₂ powders and different sizes of element powders.The effect of compaction process on the microstructure and mechanical properties of Ti-185 alloys prepared by different particle sizes of element powders was investigated. The results indicate that the Ti-185 alloy has the highest green density under the following conditions：a pressing pressure of 800 MPa， a dwell time of 80 s and a pressing rate of 1 mm/s，which can be considered to be the optimum pressing process. The smaller particale size of Ti-185 alloy is， the higher sintering density of alloy is.The smaller particle size element powder is favorable to shorten the atoms diffusion distance of alloying elements during the sintering process， resulting in enhancing mechanical properties of Ti-185 alloy.Consequently，the sample with the minimum particle size displays the highest hardness （43 HRC） and strength （1 438 MPa）.