Aiming at the accidents caused by moving fire source, for analyzing the influence law of moving fire on ceiling temperature of tunnels, through Fire Dynamic Simulator (FDS), the processes that fired vehicle with 20MW Heat Release Rate (HRR) travels at the speed of 0km/h (static in tunnel), 40km/h, and 60km/h, respectively in tunnel with natural ventilation are simulated. The longitudinal temperature distribution, change law of peak temperature, and its influence factors when moving fire stops and becomes stable combustion in tunnel are specially analyzed. It indicates that ventilation is main influential factor to the temperature in tunnel fire. Moving fire causes air turbulence and breaks the circulation balance of hot smoke and cold fresh air caused by ceiling jet in tunnel, making tunnel fire process more complicated. On one hand, the airflow filed movement induced by piston wind wake of moving fire promotes mixture and combustion of fuel and air, on another hand, it blocks the spread of heat released in the direction opposite to fire movement in certain degree and also entrains high temperature airflow into its spread. The research provides guidance for the study on mechanism of tunnel fire with moving fire as well as relevant fire fighting and rescue technique.