Abstract: To improve image quality of subpixel imaging further, quantitative evaluation of image quality of subpixel imaging system based on MTF was proposed. The MTF of two main modes of CCD subpixel imaging was derived. Taking minimum contrast ratio of human eye 0.05 as threshold, analysis showed that theoretical limiting resolution of interlaced sampling mode and four-point sampling mode were improved to 1.4 times and 1.86 times respectively, and MTF values at Nyquist frequency of two modes were increased by 0.110 6(27%) and 0.167 9(41%), respectively. Evaluation of MTFA in(0, 0.5) illustrates that two CCD subpixel imaging modes both have better image quality than CCD common imaging mode, and the image quality of four-point mode is the best. A mathematical model for simulating CCD subpixel imaging using Matlab was established, the results of simulation of bar-target verify the correctness of the analysis based on MTF.