Abstract: The paper studied the operation and separation performance of hydrocyclone separating light solid particles from liquid medium.The result shows that the pressure of hydrocyclone increased with the increase of inlet flow rate,and the overflow splitting ratio increased with the increase of PDR.The separation efficiency is almost no changed as the length of tail pipe increased.The separation efficiency increased with the increase of inlet flow rate,,and close to an asymptotic value of less than 100%.With the increase of overflow splitting ratio,the separation efficiency increased at first,and then when it reaches a maximum value,the efficiency become decreased.