Abstract: It is theor etically demonstrated that singular spectrum analysis(SSA) is a general-ized power spectrum analysis in this paper. Its generalities and applied features are as follows:(1) SSA possesses more stable identification ability as well as the intensification showing action for the period signals; so that it is excellenter than maximument ropy spectrum analysis(MESA) to ident if ypredm inant period signal and to enhence showing of sigmal; (2) Its manner of ident if ying and descripting signals is a frequency dom ain analysis by means of the time domain properties, namely the manner of both combination of time and frequency domains, thus SSA is useful to the diagnosis and forecast for weather and climate; (3) SSA is no to nly applicable to sine signal detection but also to non-sine signal. The calculated cases have virtified above results.