A coordinate system of tapered planar double-enveloping worm is selected reasonable.The curve surface structure of the basis tapered planar double-enveloping worm gear is analyzed.The curve surfaces is constructed by using MATLAB and numerical model is built.The solid model and motion simulation of tapered planar double-enveloping worm gear are carried out by the 3D solid modeling software of Pro/E and the simulation result is analyzed and verified futher.