An experimental study was performed on a forced convective heat transfer in a developing region of a plane wall jet for a gas-solid two-phase flow at slit Reynolds numbers ranging from 1700 to 3300. Detailed measurements of a flow involving glass spherical particles were carried out by a modified laser Doppler anemometry with a particle size discrimination. Heat transfer coefficients in a single phase flow presented a maximum in the transition region from the potential core to the developed flow. The presence of particles in the potential core region induced a velocity fluctuation in flow direction, and increased Reynolds shear stresses and heat transfer coefficients. Meanwhile, heat transfer coefficients decreased with loaded particles in the developed flow region and the measured Reynolds shear stresses were also simultaneously decreased. The heat transfer characteristics of the two-phase flow well corresponded to the shape factors of mean velocity profiles in the inner layer of a wall jet boundary layer flow.