One of the biggest problems to predict the bending fatigue life of gear is lack of S-N data from the standard gear specimen. It is expensive and long time to spend to do the specimen tests. The bending fatigue property data from database is not enough to fulfill the engineering needs. To solve the problem, multiaxial methods are used to predict the bending fatigue life of gears and FEA method is used to analyze the stress of gear teeth root. Result shows that McDiarmid model, Findley model and Maximum shear stress model fulfill the engineering needs and McDiarmid method is the most accurate.