Synchronous belt drive consists of an endless belt whose inner surface had equally spaced steeth and of belt wheels which have the corresponding teeth and is a kind of new type belt drive which had synthe sized all the good points of belt drive, chain drive and gear drive, while working, the teech of the belt and the gullets of the gear joggle each other to transmit the motion and the dynamic force. Synchronous belt drive has such features as exact transmission ratio, nonsliding, constant velocity ratio which can be gained, even mition, absorption of vibration, little noise, the big range of transimission ratio which can normally reach 0.98, compacting structure, the suitability to multi-axis transimission, no need of lubrication no pollition and so on. Therefore, the product is allowed and where the working condition is poor and can widely be used in machinery drives, such industry as automabiles, machine tools, chemical engineering, light industry, mining, instruments, oil industry and so on as well as all kinds of other machinery drive.