Abstract: According to the relevant theory of the signals and systems, a test method for frequency response of the PIN photoelectric diode detector was proposed. The test system realized by the method includes the light source of the narrowband pulse laser, the attenuation device of the light intensity and the photoelectric detector, etc. Firstly, the photoelectric detector received the signal of the narrowband pulse laser which went through the attenuation device, meanwhile, the rise time of the corresponding signal waveform was obtained by the digital oscilloscope. Then, according to the relevant calculation formula, the frequency response of the photoelectric detector was got. Finally, the error of test results was analyzed. The experimental result shows that the relative error by this method is about 6% of the detector whose theoretical frequency response bandwidth is 10.6MHz, and the test method is simple,feasible and applied widely.