College students are facing challenges to present their ideas by writing a paper because they rely more on information from computer and web. The purpose of this paper is to present a novel computer aided assessment system, to assess college students’ writing ability. The CAAS system comprises of an expert team, a set of achievement standard for assessment, and software systems to conduct data analysis and store related information. It has been used by institute in U.S. It yields face validity and consistency reliability. Objective evaluation results will be provided by randomly-assigned multiple reviewers. CAAS can assist college students improve writing skills, can describ a brief picture and detailed information for both school administrators and policy makers as well.