Single-pixel imaging is a novel computational imaging technique that uses only a single-pixel detector to acquire the image of an object with the help of spatial light modulation. In the terahertz band, to overcome the problem of scarcity of array detectors and realize sub-wavelength imaging in nearfield modulation, a continuous terahertz single-pixel subwavelength imaging system is presented based on an optically pumped silicon wafer all optical modulator with a spatial resolution of λ/7.62. The imaging results on the resolution test chart show that when the imaging details are not of particular interest, thick silicon wafers can be employed to obtain large modulation depths, and the compressive reconstruction algorithm can be adopted to suppress noise and smooth the output images. To pursue higher imaging spatial resolution, thin silicon wafers are needed to reduce the crosstalk between modulation units, and the correlation reconstruction algorithm is employed to retain more image details. This study provides a concise reference for terahertz subwavelength imaging.