Double layers of 150 mm?150 mm plastic scintillator arrays are used to locate the cosmic ray. Both layers of arrays are read out by wavelength-shifting fibers, which are bundled and coupled to image intensifier and ICCD camera. The light signal is delayed more than 200 ns by the image intensifier, so the ICCD can be pre-triggered by an external fast coincident signal. This cosmic ray positioning system is used to measure the time resolution and photon transfer time of the time-of-fly detector for the common test platform based on cosmic ray. Compared with traditional cosmic rays test, the data-taking efficiency of this system increases more than 30 times because of multi-point readout and higher position resolution. The test results show that the time resolution of the time-of-fly detector is better than 200 ps, which satisfies the requirement of the common platform based on cosmic ray.