The Gaborexpansionbased time frequency filtering is employed to process measured signals before conducting parameter identification. With Gabor expansion, the local characteristics of a signal can be shown in the timefrequency domain, according to which the properties of responses are acquired and the response signals can be filtered by elimination or interception. This technique can be applied to both stationary and nonstationary signals. Attribute to this technique, more information about the signals and systems can be gained, such as the distribution of natural frequencies, energy assemble functions, quantity of properties contents in each channel.