Abstract: Twenty seven model tests designed through orthogonal principle have been performed to search for the relationship between the performance of geogrid reinforced steep slope and its affecting factors. Based on the test data, the affecting factors have been put in order according to their contribution to the performance of reinforecd steep slope by error analysis and variance analysis, meanwhile the factor’s weight has been obtained by the aid of AHP(Analytical Hierarchy Process) method, succeeding in finding out the measurement index to evaluate the performance of reinforced steep slope by applying the method of fuzzy cluster. The rationality of the classification and utilization of the failure mode has been discussed and some suggestions have been pressented.