In this thesis, we design and implement an On-Line assessment system. It is interoperable to every E-Learning platforms conformed to SCORM. In this On-Line assessment system, we provide seven kinds of test formats; it can dynamic adjust the pointer of difficulty; in the ¡§New Examination Paper¡¨ function, we increase module, it can lighten the load of teacher when they set the examination paper; When students on their examinations, every students will see different sequence of questions and items in questions.