Contact characteristics and hobbing cutting of cylindrical gear with cubic spline tooth traces are investigated.On the basis of the derivation of the hobbing cutter’s tooth surface,the hobbing generated method and gearing theory,the mathematical model of cylindrical gear with cubic spline tooth trace was developed.And,the tooth contact analysis model in which the assemble errors was also considerated,was established on the conditions of continuous tangency of two contact surfaces.The computerized simulation of meshing and contact shows that the meshing characteristics of the modified gears can be improved by using the generating tool with parabolic curved profile which obtains a parabolic transmission error curve;the sensitivity of contact pattern of the cylindrical gear with cubic spline tooth traces can be reduced by adjusting the position of control nodes.