The invention discloses a steel rail heat treatment device. The steel rail heat treatment device comprises a heat treatment mechanism, a water supply mechanism, a gas supply mechanism, a main frame and a steel rail holding mechanism for holding a steel rail. The heat treatment mechanism comprises a pressure-stabilized air bellow, the pressure-stabilized air bellow is connected with an upper air bellow, a lower air bellow, a left air bellow and a right air bellow through a small vent pipe correspondingly, and first nozzles are arranged on the upper air bellow, the lower air bellow, the left air bellow and the right air bellow correspondingly; the first nozzle of the upper air bellow is arranged over the steel rail, the first nozzle of the lower air bellow is arranged under the steel rail, and the central axes of the first nozzle of the upper air bellow and the first nozzle of the lower air bellow coincide with the central axis of the steel rail; the first nozzle of the left air bellow and the first nozzle of the right air bellow are symmetrically arranged on the two sides of the steel rail; the water supply mechanism and the gas supply mechanism are connected with the pressure-stabilized air bellow correspondingly, and the steel rail holding mechanism is arranged in the main frame. The invention further provides a steel rail heat treatment method. The steel rail heat treatment device and the heat treatment method are easy, the operation is convenient, and the heat treatment effect of the steel rail can be ensured.