Unlike conventional digital cameras that used array detectors, single-pixel cameras used single-pixel detectors without spatial resolution to image targets. Due to its wide operating wavelength coverage and high sensitivity, single-pixel cameras are more advantageous than ordinary cameras in special scenarios such as special wavelengths and low light illumination, and are widely used in remote sensing detection, microscopic imaging, military reconnaissance, and other fields. A compact single-pixel imaging system was proposed, which used the working characteristics of the digital micro-mirror array to form a symmetrical folded double optical path to quickly complete differential measurement. The compact structure reduced the size of the camera system and allowed the system to use a standard Nikon lens as the imaging lens. The system had various modes such as dual-optical differential imaging, dual-optical averaging noise reduction, broad-spectrum band imaging, and dual-optical alternate sampling, and the application modes could be switched according to the different needs of the scene for reconstructed image signal-to-noise ratio, real-time frame rate, and imaging band. The experimental results based on the system prototype showed that it could realize the expected functions and achieve the corresponding performance. The proposed compact single-pixel imaging system was a successful engineering attempt of single-pixel imaging, which laid a good technical and engineering foundation for the subsequent practical application of single-pixel imaging technology.