<p>Continuously variable transmissions occupy an essential position in the transmission systems of different types of vehicles, but also face the challenge of high noise levels. To reduce and minimize the vibration and noise of the continuously variable transmission, this study designs a corresponding dynamic model and uses simulation analysis methods to analyze the effect of the modification. In addition, this study uses the fourth-order Runge Kutta method to solve the dynamic model. To perform macroscopic optimization and microscopic gear modification on the planetary gear system of the transmission, an orthogonal experimental method is used, and an improved Taguchi algorithm is designed for tooth profile modification optimization. The results showed that the displacement analyzed by simulation was between 30 and 38&#xa0;mm, while the displacement solved by the equation was between 3 and 6&#xa0;mm. The maximum sound pressure levels corresponding to operating conditions 1, 2, 3, and 4 were 49.87db, 58.43db, 68.27db, and 75.02db, respectively. And on the sun wheel inner planetary wheel, the coincidence degree before and after macroscopic optimization was 2.46 and 2.51, with an improvement ratio of 2.03%. The maximum vibration acceleration before and after modification was 1.52 and 0.75, respectively. The designed dynamic model is feasible, and the waveform variation of gear vibration acceleration after modification is smaller, which can reduce vibration and noise of the transmission. The results can offer technical support for gear modification of hybrid dedicated transmissions.</p>