Abstract: In this paper, the lateral vibration characteristics of two types of bevel gears under normal tooth meshing and rotating condition,and some of effect factors on the vibration characteristics are presented from experimental standpoint.This paper puts emphasis on the experimental investigation of vibration characteristics of a faulty bevel gear and comparing with another thickened and strengthened bevel gear.Experimental results show that both backward and forward travelling wave resonances of bevel gear with two or three nodal diameters can be occurred within the operation speeds of gear and they could cause lumped fracture fault of bevel gear.Some effective factors,such as increase in meshing clearance between driving and driven gears, unbalance of driving shaft of gear,and unbalance of loaded disk connected with driven gear,etc, could increase the vibration amplitude and stress level of bevel gear.