The invention provides a data collecting system, comprising a signal processing device which selects corresponding detection equipment to detect rays by generating selection signals according to synchronization signals, a data conversion device which converts the signals detected by the detection equipment into digital data and caches the digital data into the digital processing device, and a communication device which is connected with image processing equipment and transmits the digital data cached in the signal processing device to the image processing equipment by the connection. The datacollecting system of the invention can be extended by the number increment of the detection equipment modules, and ensure stable data collecting and converting at the same time, and transmits the data reliably.