In a toroidal CVT, power transmission is accomplished by means of a special traction oil that displays high shear resistance under a state of high pressure . A toroidal CVT can be used even with engines that generate large torque and provide excellent ratio change response and high efficiency . The history of research of the toroidal CVT are summarized and the toroidal CVT up to date is reported. The varieius aspects on the toroidal CVT are summarized ,including EHL theory , toroidal double cavity system,traction fluid ,ratio control system, traction drive system , efficiency analysis ,and so on. Finally ,The development of the toroidal CVT in the future is indicated.