The prevalence of information and communication technology (ICT) has considerably converted the means of/for publication and circulation, as well as transforming academia and English pedagogy. However, with the availability and convenience of online resources, one of the critical issues emerged is that non-native English speakers are constantly accused of committing textual plagiarism: either intentionally or unintentionally. While many writing tools and plagiarism detectors are available to help solve the problem, none of them were customized for the great population of Chinese learners of English. Accordingly, DWright—a Chinese-interfaced online writing tutorial for paraphrasing and citing English—was developed in the hope of ensuring academic integrity through the avoidance of textual plagiarism.The purpose of this study was to evaluate the design and efficacy of DWright regarding plagiarism prevention and improvement of English writing. A questionnaire and semi-structured interview were administrated to participants to test DWright and its technology acceptance model (TAM) to identify the effect of perceived usefulness, usability and user attitudes of DWright. Results show that users of DWright were in high agreement regarding the content effectiveness of all DWright-based tasks, indicating the reading activities, multiple-choice exercises and paraphrasing practices were effective to help users enhance writing knowledge and skills to avoid plagiarism. Furthermore, perceived usefulness and system usability affected DWright user attitudes significantly and positively, which mirrors their attitudes toward continued use of DWright. In this study, DWright met its users' needs by extending their knowledge to avoid plagiarism while simultaneously enhancing their paraphrasing and writing skills. The conclusion suggests that tutorial designers, content experts and subject teachers should support effective communication to improve content usefulness, so as to help users achieve their writing goals with a research proven learning and plagiarism avoidance tutorial system.