The invention provides a device for adjusting the idle stroke of a release. The device for adjusting the idle stroke of the release comprises an adjusting part and an adjustable traction rod, wherein the adjustable traction rod glidingly sleeves the traction rod of a circuit breaker; the adjustable traction rod has a thickness difference on the surface near one side of the release; when a user operates the adjusting part, the adjusting part drives the adjustable traction rod to slide on the traction rod; and thus, the action idle stroke of the execution end of the release is changed. According to the device for adjusting the idle stroke of the release in the embodiment of the invention, the action idle stroke of the execution end of the release can be adjusted; and thus, the circuit breaker comprising the release has a hot adjusting function, such that the circuit breaker can be applied in multiple circuit systems.