Non-Circular gear can be considered as a transmogrification of circular gear, because its pitch circle has been shifted from circular to non-circular. The outstanding characteristic of non-circular gear transmission mechanism in dynamics is that it could achieve the non-linear relationship between driving mechanism and follower mechanism, as a result, it can substitute for the usual transmission between cam and link mechanism, which has the following advantages:     1.Stabler,sturdier and firmer than link mechanism;     2.Stabler than cam mechanism;     3.Easier and more facile to realize shift transmission than others mechanism.     Our Company has researched and developed two principal products, one is for computer aided design of non-gear and the other, named "Cool Cut", is for automatic programming of NC incision. Now, the two products have been integrated into a strong system, called "Plusplus Non-Circular CAD", which can realize the CAD/CAM integration of non-circular gear and planet gear. The followings are its main features:     1.Satisfy many kinds requirements of different transmission ratio;     2.Design,draw non-circular planet gear accurately and simulate its transmission automatically;     3.Design,draw and simulate meshing of a pair of non-circular gears precisely;     4.Output all kinds of parameters efficiently, such as the curve of transmission ratio, the distance curve of rack;     5.Supply parameters of cutting tool of non-circular gear machining for gear shaping machine.     Application of non-circular gears