The invention discloses a heart disease intelligent diagnostic method based on case reasoning. The heart disease intelligent diagnostic method based on case reasoning is characterized in that: using various check indexes of a patient as a case to conduct searching in a case base, fining out a record which is most similar to the case as a diagnostic result; and meanwhile using water filling theory to obtain an allocation scheme of various characteristic attribute weights of the case, and rejecting redundant attributes according to the attribute weights, and thereby improving accuracy and speed of the heart disease diagnostic result. The heart disease intelligent diagnostic method comprises the following steps: defining a case expression form; constructing a history case set; using the water filling theory to conduct allocation of the characteristic attribute weights; extracting characteristic attributes according to the allocation result of the attribute weights; calculating similarity of cases; reusing the matched cases; and amending the cases. The heart disease intelligent diagnostic method based on case reasoning improves searching strategies of the case reasoning, conducts attribute reduction link through optimal allocation of the characteristic attribute weights of the cases, and ensures diagnosis accuracy and speed.