To realize high sensitivity ultraviolet (UV) detection, a UV imaging system based on digital Time Delay Integration (TDI) is designed innovatively by using a software windowing technology on the basis of a 600×500 UV Charge Coupled Device (CCD) image sensor. The noise sources of the imaging system and the influence of M-stage digital TDI on the Signal-to-Noise Ratio (SNR) of the imaging system are analyzed in detail. The influence of M-stage digital TDI technology on the SNR of the imaging system is analyzed in theory. Then, the implementation of digital TDI algorithm within FPGA is presented in detail and the interaction process of the data collection system in PC is given. The experimental results show that the UV imaging system based on digital TDI technology can obtain higher image contrast, better SNR and excellent imaging quality.