A set of fire experiments of rectangular ethanol and heptane pool fires with the same area at different aspect ratios (n), defined as the ratio of the length divided by the width of the pool, were conducted in two boundary conditions, i.e., in an open space and against a sidewall. The mass loss rate (MLR), flame shape and thermal feedback received by fuels were investigated. In an open space, the flame heights (H) of both fuels decrease with increasing aspect ratios. The MLR of ethanol pool fire is found unaffected by the aspect ratios, while the MLR of heptane pool fire increases with increasing aspect ratios. For fires against a sidewall, the MLR of ethanol pool fire does not change with aspect ratios, the H decreases with increasing aspect ratios Both flame height and mass loss rate of ethanol and heptane pool fires against sidewalls are great than those in the open space. The flame height of heptane pool fire increases with increasing aspect ratios as the oxygen consumption per unit mass of heptane required for complete combustion is higher than that for ethanol and the sidewall restricts the air entrainment. The correlations between the dimensionless flame height (H/D*) and dimensionless heat release rate ((Q) over dot*) for different fire locations and fuel types are proposed, respectively. As the air entrainment is restricted by the sidewall, for the same fuel, the dimensionless flame height of fire against a sidewall is obviously higher than that of fire in an open space. The calculation shows that the conducive heat feedback fraction of ethanol and heptane pool fires increase with aspect ratios.