Abstract: In order to investigate the influence of aeration- agitation unit口s structure parameters on aeration performance of jet flotation machine, a sample unit wi th 3 m3/h pulp throughput was designed and studied. The nozzles of the aerator and distributor were roundness and arranged annularly. Results showed that the ratio K of distributors spouting area and that of aerator, distributor and aerator nozzle0s diameter and number were the main factors which influence the aeration performanc e, the feeding pressure and aerator spouting angle affected aeration to a certain degree. The optimum size of aerator nozzles was 10 x 02. 0 mm, when ratio K change d from7 to 8, at 12. 5°spouting slope degree, the unit could aerate uniformly and steady, with enough aeration quantity. The optimal parameter of distributor nozzle was 18x 04 mm, under 0. 22 MPa feeding pressure, the aeration capacity could reach to 1. 65 m3/ ( m2:-min) , aeration uniformity coefficient was94. 31% and aeration hybri d coefficient was 1. 20, jet aeration machine performance was very well.