In automobile company it is needed to establish the collaborative relationship between the assembly company and the part manufacturing company. In this paper we established the improvement for the procurement logistics and logistics in assembly company and thus we derived the near optimal procurement cycle through the simple EXCEL simulation and the improved inventory management method for H automobile company in CHINA. At this time we adopted the pull manufacturing process instead of push manufacturing process. We resulted that the manufacturing activity of both companies was stabilized and the usage of storage area in assembly company was reduced by 50%, especially it was reduced by 100% in the case of directly delivering the parts to assembly line through the third party logistics company.