The wear problem of helical gear in EQ3126 automobile engine was discussed,it was found that the helical angle distribution of gear pair in camshaft-oil pump drive shaft of EQ3126 automobile engine was not reasonable,and the material collocation of gear pair was improper,which led to serious wear of gear pair.The contact stress of tooth surface of the helical gear transmission had greatly exceeded the allowable limit fatigue stress after solving the stress.Finally,some suggestions were put forward,such as redesign of gear parameters,modification of material pairing,control of gear processing quality and improvement of lubrication conditions.It provides reference for improving the work environment of helical gear in the transmission mechanism and solving the wear problem of tooth surface.