Flow characteristics and heat transfer of a water droplets laden how behind a backward-facing step have been experimentally and numerically investigated for the condition of isothermally heated dry wall. Two sizes of step heights were employed corresponding to Re-H = 5.3 x 10(3), 1.1 x 10(4). Numerical simulations were performed by a standard k-epsilon model for the gas phase and a Lagrangian stochastic model for the trajectories of droplets. The experimental and numerical results showed that large heat transfer enhancement existed downstream of the reattachment region and was correlated well with the ratio of time scale between an appropriate time scale of the turbulent flow and the relaxation time of droplet.