Abstract: In order to discuss the cost optimization of auto parts suppliers under diversified supply mode, a interest growth model is set up based on the Lotka-Volterra model to analyze the cooperation effect and Shapley value method is applied to analyze the interest distribution mode among multi-supplier and one manufacturing service firm. A new cooperation mode is put forward and an example is given for testifying. The results show that the value chain of multi-supplier can be optimized and the cost can be reduced if the suppliers outsource and manufacturing service firm finishes the specialized division. Each member’s benefit can be enhanced if the manufacturing service firm distributes the increased profit appropriately.