A simple analytical model of spray jet evaporation in gas-solid suspension flows has been developed, which is based on the extension of similarity correlation from two-phase jets to three-phase jets. Effects of particle concentration, ambient temperature, and solids thermal capacity on the jet structure are illustrated. It is found that the evaporation length can be significantly shortened by the increase of particle concentration while the jet boundaries are expanded. Similar reductions in the jet evaporation region can also be attained by elevating the ambient temperature or by using higher thermal capacity solids. Comparison of jet evaporation lengths from the model predictions and previously reported experiment results suggests that the proposed similarity approach is reasonable.