With challenges of the traditional "only fractional" in educational assessment, researchers have been paying more and more attention to the intelligent diagnosis and assessment of disciplines, so there are many intelligent assessment systems for students now. However, there are less researches focusing on the studies of special discipline characteristics, such as skills and ability in China. In this paper, we have established a multi-dimensional framework of mathematical knowledge ability attributes and applied it to the Mathematical Diagnostic System (MDS-KA) to help students develop comprehensively. First, the framework of mathematical knowledge ability attributes diagnoses students' cognitive structure from the three dimensions of knowledge, skills and abilities, and accurately locates students' weak points. Second, the MDS-KA system is integrated into the above framework, intelligently assesses students' learning situation, and combine with empirical research to explore the effectiveness of the framework and system. By the analysis of feedback questionnaire data, there were more than 87% of students think that the individual diagnosis report is consistent with their real learning situation and helpful for learning.