The invention provides a fast tunable reconfigurable microwave photon filter based on an electro-optic Fabry-Perot cavity and belongs to the technical field of tunable filters in microwave photonics. The device comprises a first coupler, an electro-optic modulator, a second coupler, an electro-optic Fabry-Perot cavity group and a reconstruction unit, wherein the first coupler is used for dividing a modulated carrier signal into one path of modulation signal and one path of carrier signal; the electro-optic modulator is used for performing suppressed carrier single side band modulation on the carrier signal to be modulated through the modulation signal to obtain a single side band signal; the second coupler is used for dividing the single side band signal into two paths of signals; the electro-optic Fabry-Perot cavity group is used for respectively performing tunable filter processing on the two paths of signals divided by the single side band signal; the reconstruction unit is used for coupling the two paths of signals subjected to tunable filter processing and then coupling with the carrier signal to obtain a reconstruction signal. According to the fast tunable reconfigurable microwave photon filter provided by the invention, as the tunable filter processing is respectively performed on the two paths of signals, the tunable filtering of the signals can be realized to quickly generate the reconstruction signal; in addition, due to simple structure, the small-volume integration is realized, and the energy consumption is reduced.