A self-designed experimental installation for transient heat transfer in the modelling surrounding rock mass of high geothermal roadways was elaborated in this paper. By utilizing the new installation, the temperature variation rules in surrounding rock mass of the high geothermal roadway during mechanical ventilation were studied. The results show that the roadway wall temperature decreases dramatically at the early stage of ventilation, and the temperature at every position of the surrounding rock mass is decreasing constantly with time passing by. From roadway wall to deep area, the temperature gradually increases until reaching original rock temperature. The relationship between dimensionless temperature and dimensionless radius demonstrates approximately exponential function. Meanwhile, the temperature disturbance range in the simulated surrounding rock mass extends gradually from the roadway wall to deep area in the surrounding rock mass. Besides, as the air velocity increases, heat loss in the surrounding rock mass rises and the ratio of temperature reduction becomes larger, the speed of disturbance range expansion also gets faster.