Abstract: Artificial metabolic algorithm(AMA) model is built based on enzyme catalysis from the idea of biological metabolism.The schema theorem is proposed by discussing metabolic operators function,and convergence of the algorithm is proved.Taking advantage of matching principle between substrate and enzyme,the optimal matching relation between specified enzyme and specified substrate is found by metabolic operation.The optimized result corresponds to reason for fault.In optimization process,impossible reasons are eliminated continuously by apoptosis operator.The cost for fault diagnosis is decreased.An example analysis shows that fault can be located by the algorithm efficiently and the unnecessary search space can be omitted as much as possible.