A newly developed digital image injected simulator for infrared system based on USB2.0 is introduced.The design acquires simulation data from the computer through USB bus，using the FPGA as the interface and the controller of the state machine.Furthermore，the design confirms a high-speed and real-time data transmission by introducing multi-threads technology，and implements device binding by sending vendor request to USB control endpoint.The image is acquired by the Camera Link image acquisition card and displayed on a monitor.Experiments show that the image from the injected simulator is continuous，stable and real-time，reaching up to the design specification of 100 fps.The simulator can provide a reliable data source for the IR imaging detecting system.