The fillet curve of involute gears processed by hob tip fillet is the important factor which affects the root bending stress.The goal is to improve tooth bending strength by using arcs with different radius to describe the hob tip curve and the formula for computing the best fillet radius is derived.Parametric finite element model of gear is founded by APDL and bending strength under specific load is analyzed by ANSYS/ FE-SAFE software.The results show that bending stress is reduced by 4.9% and bending strength is increased by 43% by choosing the best tip fillet hob.