The present invention discloses an radiation imaging system, comprising: an accelerator for generating rays which penetrate through the objects to be inspected and an synchronous signal; a detector with a plurality of detecting modules, adapted for detecting rays; a signal processor for generating a selection signal according to the synchronous signal, so as to select a detecting module for detecting the rays; a data converter for converting the signal detected by said detecting module into digital data, and then buffering the digital data in said signal processor; and a communication controller connected to an image processor, adapted for transmitting the digital data buffered in said signal processor to said image processor. The system according to the present invention allows high-speed and stable data acquisition and data conversion and accurate and reliable data transmission, when the data amount is significant.