The challenges in the writing classroom are caused by the lack of writing process in the conventional writing classroom. Writing goals should not focus on evaluation but for communication and the writing improvement during the process. At the prewriting stage, writers find and organize their ideas.To enhance students' writing performances and promote a long-life learning in writing, we designed a Private Social Network Learning Sites (PSNLS) system by incorporating Mindmap-Supported Writing which includes a writing E-portfolio environment. The research result indicated that this system can well facilitate the Mindmap-Supported Writing Model and effectively improve the students' writing performance in the draft and revision step. In the future, the immediate feedback and writing performances evaluation dashboard functions are suggested to be included in the system. The reasons are for self-evaluation and to track their writing improvement real-time.