Abstract. Hole cleaning is one of the key techniques of extended reach drilling. Compared with horizontal and vertical well section, the cuttings transport in inclined section is more complicated and difficult to be solved analytically, especially affected by drill pipe rotation. Computational fluid dynamics method is used to simulate the cuttings-mud two-phase flow in the annulus of inclined section. Simulation result shows that back flow is a remarkable feature of cuttings transport in inclined well section. Drill pipe rotation turns the axial motion of cuttings in annular into the helical motion. Drill pipe rotation can not only reduce the total cuttings concentration in annular, but also increase the average cuttings velocity. Section with 40～60 degree of deviation angle is the most difficult cleaned section, where cuttings concentration and pressure drop are also bigger than the rest sections.