Abstract: To reduce the moisture of clean coal in Chaochuan coking chemical Co Ltd coal preparation plant,optimized the operation pressure and speed of main shaft of GPJ-120 hyperbaric filter. The results show that under condition of coal quality unchanged,the working pressure is 0. 35 MPa,the speed of main shaft is 1. 10 r/min（for coking clean coal） and 1. 25 r/min（for 1/3 coking clean coal）,the moisture of flotation clean coal can be controlled in best limit,which has minimum effect on quality of total clean coal.