With the development of automotive active safety technology, this paper studied the protective performance of Integrated Active and Passive Seatbelt (IAPS) for occupants, and carried out a robust optimization design in order to further promote the development of Integrated Active and Passive Seatbelt (IAPS) technology and the wide application of IAPS. First of all, this paper compared and analyzed the protection performance of IAPS Conventional Pyrotechnic Seatbelt (CPS) and reversible pretension seat belt (RPS) for occupants by Madymo software. Then, taking the occupant head injury (HIC15) and Chest compression (Cdef) as the objective function, the Kriging agent model was constructed. The Multi-objective Particle Swarm Optimization (MPSO) was used to optimize 6 key parameters of IAPS, including reversible pretightening force, reversible pretightening time, pyrotechnic seat belt pretightening time, expansion rate of seat belt, limited force value of seat belt and activation time of airbag. Based on the iSIGHT multi-disciplinary optimization platform, the optimal Latin square was used to sample the optimized Pareto non inferior solution, and the Monte Carlo method was used to simulate the samples to meet the 6 Sigma robustness design criteria. Finally, the optimal solution was selected based on the risk of occupant injury. The results show that IAPS is superior to CPS and RPS in occupant protection. In addition, the multi-objective 6 Sigma robustness optimization design not only significantly reduces the head damage value (HIC15) and Chest compression (Cdef) of occupants, but also reduces the mean and variance of IAPS quality characteristics, making the design variables far away from the boundary constraints. Therefore, the consistency and reliability of product quality for IAPS are improved.