Through the popularity of technology, technology has revolutionized the way of teaching English writing. Research has shown that web-based programs are beneficial for language learning. Thus, in order to find effective ways to facilitate English writing instruction, the researcher intends to seek supports from webbased writing program. In the current research, three English writing classes (49 students in total) of a university at the southern part of Taiwan participated in the is study. Quantitative data such as students' posttest score were analyzed using ANCOVA. Qualitative data obtained through student questionnaire and teacher interviews were also collected and analyzed. The findings indicated that the students who applied web-based writing program indeed outperformed the regular writing group in most variables, especially in content, development and organization. However, problems also arise when using web-based program as the only instructional media.