Aiming at solving a horizontal stabilizer bar fracture failure, firstly, the forward horizontal stabilizer assembly model and the front suspension dynamics model were established based finite elements method and rigid flexible coupled multi-body dynamics method, the horizontal stabilizer bar displacement were extracted in limit working condition, so the strength analysis force displacement was 49.5 mm. And then the horizontal stabilizer bar was strengh analysised by adopting Nastran software, the analysis results show that the maximum stress was 977.6 MPa, it located in the horizontal stabilizer and stabilizer bar bracket and bushing joint position, there was a fatigue injury risk about it. The horizontal stabilizer bar was fatigue life analysised by adopting FEMFAT software, the analysis results showed that the minimum life was 3.37×10~4 times, the weakest place was consistent with the maximum stress position for strength analysis, it was below design requirements. And then the horizontal stabilizer bar was multi-objective optimization analysised by adopting Isight optimization integration platform, its optimal diameter was obtained, its fatigue performance meets the design requirements after optimization. The horizontal stabilizer bar bench test platform was established by loading with sine wave, the results show test results were agree with the fatigue simulation results,and it passed the test of the vehicle road. Finally, the horizontal stabilizer fracture problem was successfully solved. The analysis method combined finite elements, multi-body dynamics, fatigue mechanics, bench test and road test, It provided advanced scientific guidances for the similar structures fatigue strength analysis and optimization design.