Abstract: During the service of the suspension bridge, the time-varying load caused by the coupling of dead load, wind load and live load caused by vehicle passage causes the unbalanced force on both sides of the saddle of the main cable, resulting in dynamic contact and microslip between the main cable strand and the saddle. When the unbalanced force exceeds the limit friction force between the main cable and the saddle, the main cable and the saddle will slip. Then the suspension bridge structure instability and even collapse accidents. Therefore, it is of great significance to study the dynamic contact and microslip mechanism between the main cable strands and the saddle of the suspension bridge to improve the anti-sliding safety of the main cable and ensure the structural safety of the long-span multi-tower suspension bridge. In this study, a self-made test platform was used to simulate the dynamic contact and microslip behavior between the main cable strand and the saddle under dynamic load conditions in the actual service environment of the suspension bridge, and the dynamic contact and microslip mechanism (contact state, microslip amplitude, friction coefficient, contact pressure, etc.) between the main cable strand and the saddle under typical working condition were revealed, it was of great significance to ensure the service safety of suspension bridge. The results showed that there were differences in the contact states between each individual cable and saddle when the main cable was under dynamic load. The contact surface between the outer cable and the saddle was in a completely sliding state, while the contact between the inner cable and the saddle was in a partially sliding state close to the completely sliding state. when the main cable was subjected to a large dynamic load, it was easier for the outer cable and the saddle to slip completely, and the stratified slip phenomenon occured between the cable strands, and the microslip amplitudes of different cable strands increased from the inner to the outer layer. With the increase of loading force, from the inner cable to the outer cable, the growth rate of slip distance increased successively, and the microslip amplitude increased gradually from the fixed end to the loading end at different contact positions. The friction coefficient between the whole strand and the saddle increased rapidly, fluctuated slightly and became stable gradually. The average nominal friction coefficient of the cable strands was consistent with the average friction coefficient between the whole cable strand and the saddle. The contact pressure at the fixed end of the saddle showed a trend of slow increasing-rapid increasing-slow decreasing-rapid decrease, and the contact pressure at the loading end was basically the same as the alternating load. With the increase of the loading force increment, the contact pressure at the fixed end was basically unchanged at the beginning, and then increased slowly, while the contact pressure increment at the loading end increased linearly.