RU type circular tooth synchronous belt was taken as the research object, by analyzing the mechanism of meshing impact noise and transverse vibration noise, it had been determined that the speed was the main reason affecting the transmission noise of synchronous belt. An experimental study on the effect of speed on the vibration and noise of the synchronous belt was carried out on the vibration and noise test bench. Laser displacement sensor and sound pressure sensor were used to measure the vibration and noise signals of synchronous belt at the meshing point, and the timedomain and frequencydomain distribution curves of noise and vibration at the meshing point were obtained. Curve of noise and vibration changing with the speed shows that with the increase of the speed, the noise amplitude increases gradually, and the vibration amplitude decreases gradually. The result provides a basis for the control of vibration and noise of synchronous belt transmission