The invention provides a spring salt mist fatigue test device. The spring salt mist fatigue test device comprises a spring fatigue testing machine, the spring fatigue testing machine comprises a testing mechanism, the testing mechanism further comprises a casing pipe and a salt mist spray device, one end of the casing pipe is sleeved on a first spring seat of the testing mechanism, the other end of the casing pipe is sleeved on a second spring seat of the testing mechanism, the salt mist spray device is arranged in the casing pipe, the salt mist spray device comprises a water spray hole and an air jet hole, the water spray hole is connected with a brine tank through a pipeline, the air jet hole is connected with an air source device through the pipeline, the fatigue test for a spring is completed by the testing mechanism, the casing pipe arranged on the testing mechanism is utilized to form enclosed space between the first spring seat and the second spring seat, the salt mist spray device disposed in the casing pipe is utilized for spraying salt mist on the spring, the salt mist spraying is performed while the spring is subjected to the fatigue test, the spring fatigue test and spring salt mist test can be simultaneously performed, and thereby the spring fatigue corrosion test can be completed.