Oval bevel gear is introduced as a new gear transmission type of intersecting axes, in which high-order, denaturing and eccentric one are included. Based on the theory of spatial engagement, spatial spherical coordinate system of the noncircular bevel gearing was developed and a generalized tooth profile equation of noncircular bevel gears was also proposed. The gear profile can be enveloped for the generating movement between conical cutter and oval bevel gear according to the envelope principle of conjugate profiles. Then a new and general parametric design method for oval bevel gear was founded. The classification and gear variability condition of oval bevel gear were discussed. Meanwhile, its pitch curve, addendum and dedendum curve were studied, and the corresponding equations were deduced. A roll check experiment is performed on the prototype workpiece. Then the influences of motor speed and load on transmission ratio were analyzed. Finally, the design method, profile generation method and manufacture method of oval bevel gear were certified as correct by comparing experimental curve of transmission ratio with theoretical one.