Abstract: The existance of cuttings bed in slant and horizontal hole sections is one of the important causes of poor cementing of complex structural wells. The causes of cuttings bed formation and the main clearge methods currently adopted in the field are analyzed . Downhole tools specially used for actively removing cuttings bed are developed, the structure and operating princples of the tools are studied. Through fluid mechanis simulation, the active cuttings bed removing mechanism of the tool is verified. Test of the tool in CB26A-7 well in Shengli Oilfield is introducd. The research has directive significance for improving cementing quality of complex structural wells.