Abstract：Objective To develop a synchronizer for synchronizing visual stimulus and response acquisition devices to reduce the
measurement error caused by serial port delay. Methods The phototriode (PT908) was used to collect optical signal of visual
stimulation, which was converted into electrical signal and output TTL, RS232 levels through microprocessor. The output interface
was connected with the acquisition device. Results The time difference between the output signal of the computer serial port and the
light signal presented by the monitor was collected using a logic analyzer and calculated to be about 5 ms after processing, while the
time difference between the output signal of the synchronizer and the light signal presented by the monitor could be stabilized
within 1 ms. Conclusion The synchronizer can provide 1 ms timing synchronization accuracy to improve the accuracy of visual
stimulation experiments, and provide help for the experiments of visual science, brain science and other disciplines.