Abstract: A fault diagnosis method for analog circuits with low testability using sensitivity analysis and support vector machine (SVM) is presented in this paper. The transfer function poles and zeros sensitivity of circuit under test is analyzed. The ambiguity group is determined according to the poles and zeros sensitivity with respect to the components and the testable components set is obtained. The poles and zeros sensitivity analysis theoretically determines all of the diagnosable circuit components and SVM has advantages of simple structure and strong generalization ability. Experimental results prove that the proposed method for diagnosing analog circuit fault using poles and zeros sensitivity analysis and SVM is effective and the fault diagnosis accuracy of the method is more than 99%.