Abstract: Aiming at the large number of mechanical and electrical equipment of small hydropower stations in our country at present,especially the mixed flow horizontal turbine is seriously aged and cannot reach its rated output and other problems,the optimal design of runner and water guiding apparatus of mixed flow turbine is discussed.The test shows that the efficiency,output,noise and vibration of the unit were obviously improved by optimizing the hydraulic design of turbine runner and installation angle of the movable guide vane outlet.