The invention discloses a low-delay all-digital monitoring system, which comprises a video signal coder, a computer and a display which are orderly connected, wherein the video signal coder comprises a camera module, an analog-digital conversion module, a CPU and DSP module and a first network control module, wherein the computer comprises a second network control module, a CPU module, a display control module and a front end control module. Except for compressing and coding or packing and transmitting YUV format signals, the CPU and DSP module further abstracts the YUV format signals into video signals, then packing an transmitting, the computer displays the video signals on the display after receiving the video signals, thereby the condition of the monitoring front end can be observed in real time, when the camera module needs to be adjusted, the control orders are analyzed by the CPU and DSP module, and results are transmitted to the camera module, and simultaneously, the camera module embodies the executing results of the control orders on the display. Video signals whose low-delay is the same with a simulated system can be seen from the control station, the complexity is reduced, the cost is low and the maintenance is easy.