Ring synchronous belt, with the extensive application of synchronous belt transmission, rising to its requirement, synchronous belt transmission will have the following trends: 1, improve the quality and the service life of the synchronous belt with the proposition of motivation to BRECOFLEX synchronous belt transmission, high transmission quality and longer service life has become the urgent request of the user, so synchronous belt transmission, will in future to strengthen the direction, that is, from strength, precision and service life, noise and other aspects to improve the quality of the synchronous belt transmission, the synchronous belt by wearing parts into durable parts with high strength, long service life. With the improvement of requirements for using synchronous belt transmission, the synchronous belt transmission is also exposed many problems and defects, need to be solved in theory and in experiment to analyze the improvement. At the same time also requires perfect synchronous belt transmission design method provides users. These requirements are to promote the development of the synchronous belt transmission theory research. According to the data reported, at present abroad in theoretical research on synchronous belt transmission.