With the rapid development of Japan-oriented Software Outsourcing, software professionals demand increase sharply, Japanese ability is the basis for software professionals qualified software outsourcing, the evaluation for the Japanese Language Proficiency of students with software outsourcing has great significance to promote China's software outsourcing development. This paper, researches with rough soft sets theory. First, through investigation and comprehensive analysis and combined the previous studies results to establish evaluation index system; Second, researches the maths models constructed by 6 definition, including: rough soft sets, contrast matrix, up-down row sum, up-down column sum, up-down scores and quality sorting; Finally, according the evaluation steps, evaluate the Japanese ability of nine Japan-oriented Software Outsourcing students, and obtains the sort result. The results show that rough soft sets theory considers various factors and objectively reflects the actual situation, the evaluation results are accurate and reasonable, simple and feasible, is a scientific method.