Due to the advantages of large contract ratio, strong bearing capacity and smooth transmission, the high contact ratio (HCR) wide helical gear transmission is widely used in ships, aerospace and other fields. The complex and varied internal and external motivation and assembly errors can easily cause structural deformation of transmission components, which leads to meshing misalignment and exacerbating system vibration during its transmission process, resulting in a sharp decline in its dynamic service performance. In this paper, a rigid-flexible coupling dynamic model is established for the HCR wide helical gear transmission system, considering that the influence of meshing misalignment on the contact state of tooth surface. Then, the influence mechanism of meshing angle misalignment on its coupling vibration characteristic is investigate by using the model. It provides theoretical support for the design and dynamic performance optimization of HCR wide helical gear transmission system.