Abstract: Aiming at the conflict of case matching，a new method of case matching based on importing probability is proposed，and a complete theory is given　which is about the deciding and importing of probability，the calculating of final similarity assessment.First，it filters case by judging the value.Then it imports probability which can change the final similarity by influence factor.At last，it calculates and compares the final similarity assessment to get the optimal case.Calculating result indicates that it improves time，effect and accuracy of case matching.