Multispectral imaging technology integrating spectral measuring with imaging technology, can detect the spectral and geometric characteristic of target simultaneously. The multispectral imaging has technical advantage in restraining the clutter backgrounds and identifying target. A multispectral imaging system with four channels working in Mid-wave Infrared (MWIR) band has been developed. Using the narrow optical filter and the infrared Focal Plane Array (FPA), the staring multispectral imaging system can work based on time sequence sweeping. According to the detector performance, the temperature sensitivity of each channel has been analyzed. For improving the sensitivity of each spectral channels，optical filters were schemed carefully to extend the integral time of the detector. Using the developed MWIR multispectral imaging system, the imaging test has been carried out, and the results of each channel have been compared.