The invention relates to a multi-channel sampling high-speed signal collecting and processing system which comprises a mainframe module, a power module, a clock module, a data collecting module, a signal processing module and a user-defined high-speed backboard module. The mainframe module is a display control unit of the system and is responsible for controlling the working state of the system and displaying system formed images. The power module provides a 3.3 V-5 V voltage for the system. The clock module provides a synchronous clock source for the system and is used for synchronizing the working state of the system. The data collecting module is used for synchronously collecting intermediate frequency analog signals, carrying out pre-processing operation such as data caching and significance bit extracting on the collected signals, and synchronously transmitting the pre-processed data to the signal processing module. The signal processing module is responsible for receiving the pre-processed data sent by the data collecting module and transmitting generated original image data to an upper computer. The user-defined high-speed backboard module connects the modules through corresponding connector plug-ins. According to the multi-channel sampling high-speed signal collecting and processing system, ninety six channels can synchronously collect intermediate frequency analog signals at the 400 MHz sampling frequency, and processing such as data extracting, related operation, image inversion and image fusion can be carried out on the collected data.