The mass burning rate and flame tilt evolution for radiation-controlled rectangular hydrocarbon pool fires with cross air flow (ranged from 0 to 3 m/s) in a reduced pressure atmosphere at high altitude (altitude: 3650 m, 64 kPa), are experimentally studied, with rectangular acetone pools with same surface area but different aspect ratios n (n = L/W, ranged in 1-8). It is found that burning rate increases a bit faster with flow speed in reduced pressure. For condition of shorter side facing the flow, the increase of mass burning flux with flow speed is found to be dominated by the three side wall dimensions (except the leading one) in both pressures. However, in case of longer side facing the flow, a stagnant layer theory solution to include ambient pressure (due to the fuel vapor gas phase density is proportional to pressure) and cross air flow speed by taking the shorter side as characteristic length scale is proposed to correlate the data well in both pressures. For the mean vertical flame height and flame tilt angle, characteristic length scales including pool aspect ratio are proposed to apply available classical models to this special condition, which well correlate the obtained data. (C) 2014 Elsevier Ltd. All rights reserved.