Abstract: In this paper,one kind of practical derust brush mechanism with constant friction torque operation inside pipe is developed.In order to modify the derust effectiveness,static analysis of the mechanism is conducted.Considering the eccentricity between pipe line axis and central line of robot and nonideal pipeline roundness,dynamic model of brush mechanism is set up,then dynamics respose is formulated,the results offer theoretical basis for its derust quality control and brush mechanism parameter optimization.