The structure of oscillating teeth end face harmonic gear is introduced on the basis of introducing the asymmetrical coefficient for describing the degree of tooth asymmetry. The engagement theory and shape equationof symmetry tooth is extended to the asymmetrical tooth of the oscillating teeth end face harmonic gear drive,thus the conditions of instantaneous transmission ratio constant and the equations of all meshing pair for asymmetrical tooth of the oscillating teeth end face harmonic gear drive are deduced.