The mainstream terahertz imaging technology has mutual constraints in imaging speed, resolution, sharpness and manufacturing cost, etc. A fast terahertz wave imaging technology based on a light-controlled spatial modulator is proposed. This technology realizes the single-pixel terahertz detector by integrating the new silicon-based terahertz modulation material with the commercial Digital Light Processing(DLP) device. The influence of terahertz beam distribution characteristics and Gaussian background on imaging results is further analyzed. An effective optimization method is proposed. The rapid imaging results confirm that this new technology can significantly improve the imaging resolution and clarity.