Abstract: A infrared single-photon detecting system has greatly improved the performance of the weak light detection system due to its ultra high sensitivity and SNR. Based on TSMC 0.35 m CMOS process, a design method for digital mode infrared ROIC and its application system were proposed. The system included high-segment pixel TDC and low-segment global shared TDC controlled by OSC multiphase clocks. The implemented circuit was operated at frame rates of 1 kHz with data output in a series mode, also it has a time resolution of less than 1ns along with a 3 s measurement range under 170 MHz reference frequency condition, which can finally satisfy the application of ranging and imaging after relevant data processing.