The invention discloses a lift car roof colliding reset device which comprises a lifting mechanism, a buffer tank, a buffer piston and an electric heating device. The buffer tank is arranged above the lifting mechanism, and can be driven by the lifting mechanism to ascend and descend. A through hole is formed in the top of the buffer tank, and a part of the buffer piston stretches into the buffer tank through the through hole. The buffer piston is in sealing fit with the through hole and can move along the through hole. A first limiting plate is arranged at the end, located outside the buffer tank, of the buffer piston and is opposite to the top of the buffer tank. The electric heating device is arranged on the buffer tank and can be used for raising the temperature of air in the buffer tank through heating. According to the lift car roof colliding reset device, the roof colliding speed of the buffer tank can be reduced or a lift car can be braked, a counterweight ascends through the lifting mechanism, and the reset operation on the lift car is facilitated. Compared with the manner of lifting the counterweight through a jack in the prior art, the safety of a lift is greatly improved.