In wet processing, starch separation is one of the most important steps to prepare pea protein from pea slurry. The effect of single stage hydrocyclone on the separation of starch in pea slurry was investigated under different conditions such as feed pressure, stock ratio and feed liquid concentration. According to the experimental results, when the feed pressure was 0.6 MPa, the stock ratio of bottom overflow was 0.32, the soluble component was 2.86% and the insoluble component was 8.61%, the separation efficiency of starch and other insoluble components in pea slurry entering the bottom flow reaches 84.50%, and that of protein and other soluble components entering the overflow reached 73.74%. The operating conditions of the single-stage cyclone provide the basis for the separation process research of the multi-stage cyclone.