The invention provides an indicating instrument detecting system and method. The detecting system comprises a detected indicating instrument, a standard source, a standard meter, a CMOS camera, a data acquisition card and a computer, wherein the standard source is connected with the detected indicating instrument, the standard meter and the computer, the CMOS camera is connected with the data acquisition card, and the data acquisition card is inserted into a card slot of the computer; the standard source outputs testing benchmark electricity quantity to the detected indicating instrument and the standard meter according to a testing benchmark value; the standard meter outputs a standard value generated according to the testing benchmark electricity quantity to the computer; the CMOS camera acquires an image of the dial plate of the detected indicating instrument in real time, and the image of the dial plate is transmitted to the computer through the data acquisition card; when a pointer in the image of the dial plate coincides with a scale value corresponding to the testing benchmark value, the computer sends a stopping instruction to the standard source, and a current standard value output by the standard meter to the computer is recorded; whether error exceeds an error standard value or not is judged by the computer according to the current standard value and the testing benchmark value, and a judgment result is output.