The main purpose of the research is to use the educational assessment on the basis of Evidence-Centered assessment design（ECD） to build a intelligent diagnostic and remedial instruction system in The “Quantity and Measurement” Indicators of Mathematics in Grade 4 based on Bayesian Network. The system can be used to diagnose the mistaken types and the student can receive in-time computerized adaptive remedial instruction. Evaluation, Diagnosis, and remedy can be achieved simultaneously. The results： 1.The Bayesian networks evaluation mode and evidence- Centered assessment design apply effectively to the diagnosis of students’ mistakes and sub-skills. 2.The progress of student is significant after taking the Computerize adaptive remedial instruction. 3.One of the program advantages is to give individual remedy instructions based on mistaken types, and it is un-available by traditional paper test.
