A novel ultra-high-gravity mini-hydrocyclone was designed. One-factor experiments and two-factor experiments were conducted to study the effects of the feed flow rate, split ratio, feed concentration and vortex finder diameter on separation performance of rice starch and potato starch, respectively. The results indicated that the effects of the feed flow rate, split ratio and feed concentration on the total separation efficiency for rice and potato starch were remarkable in the one-factor experiments; the feed flow rate, split ratio and vortex finder diameter significantly affected the total separation efficiency in the two-factor experiments. The interaction effects between the feed flow rate and split ratio significantly affected on the total separation efficiency, and the interaction effect between the feed flow rate and split ratio had a high significance to the total separation efficiency.