The rectangular pools with the same length of 100 cm but different widths of 4 and 20 cm are used to conduct experiments of flame spread over jet fuel of RP-3. The direction of longitudinal air flow is same and opposite to direction of flame spread respectively. Six air flow velocities 0.45, 0.88, 1.3, 1.73, 2.15 and 2.57 m/s are employed. The spatial temperature distributions and convective heat dissipation at pool bottom are examined using thermocouples. The heat loss is negligible for 10 mm-thick fuel layer, but it is evident for 3 mm-thick fuel layer. The integral method is proposed to calculate the flame radiation imposed to subsurface flow region. The gas-liquid heat transfer model including liquid-phase convection, flame radiation and convective heat dissipation is established for calculating energy balance involving flame spread over RP-3. The calculated heat fluxes follow well with experimental measurements, regardless of direction and magnitude of air flow. The current findings possess potential application and practical guidelines for fire prevention of liquid fires under longitudinal air flows. In order to restrict flame spread, it is a feasible method to cut off liquid convection or shield flame radiation.