The invention discloses a test method of a hangar high pressure water mist characteristic. The test method comprises following steps of first, regulating a test device to prepare for a test; second, installing a to-be-tested spray head in the test device, starting the test device to inject water into the spray head, then starting a laser particle analyzer in the test device so as to detect particle concentration of water mist sprayed by the current nozzle; and third, outputting particle concentration data detected by the laser particle analyzer to an external computer, completing the test of the spray head atomization characteristic. According to the test method of the hangar high pressure water mist characteristic, steps first to three detect the particle concentration effectively by using the laser particle analyzer, then detect the spray head atomization characteristic.