The influence of the parameters of PbSe photoconductive infrared detector on the photoelectric response was simulated by the continuity equation of semiconductor non-equilibrium carriers. A small-scale pixel x-y addressable PbSe photoconductive focal plane array （FPA） detector was developed experimentally. The pixel size was 500 μm×500 μm， and the pixel pitch was 500 μm. The photoelectric response performance of the pixels of the PbSe FPA detector was experimentally characterized， and the effective pixel rate reached 100%. Under 500 K temperature blackbody radiation and 3.0 V bias voltage， the average responsivity and detectivity reached 110 mA/W and 5.5×10⁹ cmHz^1/2W^-1， respectively. The noise equivalent temperature difference （NETD） of the pixels ranged from 15 to 81 mK， and the average noise equivalent temperature difference was 32mK. Using a mid-wavelength infrared imaging device， the infrared thermal imaging of the PbSe FPA detector on the thermal radiation target of 350~450℃ was preliminarily demonstrated. This work lays the foundation for the subsequent development of high-density pixel PbSe FPA detectors.