In order to study the influence of face pitting damage on helical gear, the helical gears on the secondary deceleration system was taken as an object and the geometric model of gears were built and assembled by SolidWorks. Using the finite element software Workbench, the meshing position of gears set surface contact, and the mechanical properties of intact and damaged gears were analyzed. Next, the analyses of variance were done including the factors of the driving wheel speed and the number of pitting corrosion. The results showed that the rotational speed and pitting damage had a certain influence on the mechanical properties of the helical gear. With the increasing of the number of pitting corrosion, the influence was more and more significant. At the same time, considering the mechanism of pitting corrosion, the friction coefficient was adjusted and some correlation between friction and pitting corrosion was determined.