Product is divided into four types which are hardware, software, processing material and service. Processing material is one typical kind of product among them. The hardware produced in several steps could be divided into single independent unit which is called “working process”. However, the flow is continual and there is no independent “working procedure” during the production of processing material. So how to evaluate and improve process achievement in the manufacture process of processing material becomes the study goal of this paper. This paper aims to explore the method for the process capacity evaluating of processing material as well as improving by researching a case on super-higher molecular weight polyethylene porous plastic. Statistical technology and knowledge are used together to improve the comprehensive ability of process.