<p>This study investigated the effects of fire source height on flame morphology and tunnel roof temperature distribution in moving fires within a 1:10 scale rectangular tunnel. Experiments were conducted under controlled conditions by varying fire power, fire source height, and fire source moving speed. First, the flame tilt angle increased with fire source moving speed but eventually reached a plateau as speed continued to increase. For the same moving speed, the flame tilt angle decreased as the fire source height increased. By incorporating fire source power and fuel combustion heat into the analysis, a predictive model for flame tilt angle applicable to gas fires was developed. Flame height was found to be closely related to flame tilt angle. As the fire source moved faster, flame height decreased and stabilized once the speed exceeded 1.0 m s⁻¹. Additionally, higher fire source positions led to lower flame heights. In terms of tunnel roof temperature distribution, it was observed that at low fire source speeds, increasing fire source height significantly elevated the peak roof temperature. Moreover, higher fire power amplified this effect. However, as fire source speed increased, the influence of fire source height on peak roof temperature gradually weakened. Finally, the validity of the proposed temperature prediction model for moving fire sources was confirmed by fitting temperature rise and fall phases using appropriate time intervals. Experimental data across various fire source heights were integrated into the maximum ceiling temperature model, demonstrating its accuracy and applicability.</p>