Abstract: The fluctuation contact pressure between contact wire and slide in pantograph-catenary system during train operation can affect the temperature characteristics of the sliding friction pair. High contact temperature will accelerate the wear of contact wire and slide, leading to the reduce of the service life of contact wire and slide. To investigate the impact of fluctuating contact pressure on the contact temperature of the slide, a three-dimensional finite element model is established with COMSOL software to simulate the thermal phenomenon of the sliding friction pair. The accuracy of the simulation model was validated by experiments. The temperature characteristics simulation under various working conditions is carried out. Both fluctuating amplitude and fluctuating frequency of the contact pressure will cause the fluctuations of contact temperature. Under fluctuating contact pressure conditions, at a constant sliding speed, higher contact current leads to larger fluctuation amplitude of contact temperature, and at a constant contact current, higher sliding speed results in higher contact temperature. The thermal flux density distribution of the contact surface on the slide shows a "saddle" shape under low speed and small current conditions, while it shows a "U" shape under high speed and large current conditions. The thermal flux density under stable contact pressure conditions is higher than that under fluctuating contact pressure conditions.