The nonlinear output frequency response functions(NOFRF) which is derived from the Volterra series can facilitate the analysis of nonlinear systems in frequency domain, it is a one dimensional function of frequency. The paper introduces the structural damage detection method which is based on NARMAX model and NOFRF. An experimental study demonstrates the feasibility of the structural damage detection method. Because the nonlinear characteristics of system can be used for the detection of structural damage, and is sensitive about the state of system, in addition, the structural damage detection method which is based on NARMAX model and NOFRF is a nonlinear method for analyzing the state of system, the characteristics extracting from system is a nonlinear characteristics, so the damage detection method can be used for the detection of structural damage, and has the advantage which is sensitive to the state of system.