In view of the fact that current avalanche photodiode (APD) test platforms have the disadvantages of redundant equipment and low test efficiency, an APD performance test system with field programmable gate array (FPGA) as the control core and TDC-GPX as the high-precision time-to-digital conversion chip is designed, which can realize the automatic test of APD performance parameters. In this work, a design method of stable single photon pulse signal output is designed, and the design scheme of photon counting, data processing and post-pulse parameter calculation using time-to-digital conversion is introduced. The experimental results show that the integrated light source of the test system has a full width at half maximum (FWHM) of 46.6 ps, a peak amplitude of 304.4 mV, and an amplitude jitter of 3.7%, which meets the requirements of the APD test for the input single photon source. It indicates that the test system can effectively test the APD performance parameters, and the test efficiency has been greatly improved.