The split-torque gear transmission structure offers advantages such as compact size, high reliability, quiet operation, and minimal energy consumption, meeting the design specifications for the main reduction system in modern helicopters. When gears rotate at high speed, the contact friction between the meshing surfaces generates a large amount of heat, which may lead to overheating of components, causing fatigue pitting, tooth surface adhesion, and other failures. Therefore, this study outlines the principle of calculating the synchronization angle under system error conditions, analyzes the calculation method of the quasi-static load sharing coefficient of the split torque gear transmission system, and explores the influence of the synchronization angle on the tooth surface contact characteristics of each branch. The results indicate that the reason for the uneven load on the torsional transmission structure during system operation is due to the different meshing deformations of two identical gear pairs, and the elastic displacement generated by each gear has different deformation superposition effects. By analyzing the sensitivity of the average load coefficient and synchronization angle, the variation law of the average load performance with the inherent parameters was obtained, providing a reference for the vibration reduction design of the split type torsional gear transmission system.