Many non-native English speaking (NNES) graduates are required to write academic papers in English; consequently, recent research in the past decade has been devoted to investigating the usefulness of genre-based Writing Instructions (GBWI) on learners' writing cultivation. There is little specific guidance, however, on how GBWI can be employed in online learning environments. The study aimed to design an e-learning tool with a Chinese-based interface and to evaluate its perceived usefulness on users' English academic writing development. Needs analysis and GBWI were employed as the main approaches for the system development, for which 32 participants involved in the trail. The results indicate that the participants considered the system useful and helpful while learning English academic writing and extract the design principles derived from the empirical results in the study. The findings provide both learning content developers and e-learning tool designers with developmental insights for graduates to acquire academic writing ability in English. In conclusion, this study contributes to the understanding of GBWI acting on the NNES engineering graduates' development of English academic writing knowledge and skills with the development of e-learning tools.