With the broadest application and development of modal analysis method， the demands such as less restrictive conditions and to increase the reliability of an analysis have been increased for more convenience in engineering applications. This paper presents a new modal analysis method without input data and any analytical models. Harmonic parameters of a point response can be extracted by spectrum analysis using the measurements obtained from structural testing. Preliminary results calculated by discrete deconvolution techniques are further modified by the frequency domain space curve fitting method. Modal parameters of system just come from a combination of these corrected results. The performed analysis and validation of real data indicate that the approach is feasible for engineering. Therefore， this paper provides the effective estimation scheme of modal parameters for experiment research on the system dynamic performance.