Based on the preliminary research findings in the project-based flipped learning model in Business English Translation course, this study designed a process-oriented assessment model for this course and tested its efficacy by an empirical study on 181 third-year English major students divided into three experimental class and three control class under a flipped learning context. The process-oriented assessment model in Business English Translation course is both synchronic and diachronic, by incorporating multiple assessment subjects including both the teacher and the students and the complete learning activities before, during and after class. This study conducted a pre-test and an after-test to examine the students' command of key translation knowledge and skills, and meanwhile, to evaluate the improvement of students' translation competence after the implementation of the process-oriented assessment mode. Questionnaires and surveys were also employed in this study so as to collected students' response to the new assessment model. The data and results collected from the above-mentioned research methods indicate that the process-oriented assessment model can significantly enhance students' motivation and performance in Business English Translation course.