Microstructures of evaporative liquid spray jets in gas-solid flows can be significantly altered by the variation of the solids concentration in gas-solid suspensions, In this study, experiments are conducted to illustrate the effect of the solids concentration on some aspects of microstructures of evaporative liquid jets, especially the jet evaporation length. The study indicates that, due to turbulence mixing and phase interactions among gas, solids, and evaporative droplets, the evaporation length can be shortened by as much as 45% with the solids concentration of 1.6%, compared to that in the solids-free flow. It also indicates that the thermocouple measuring technique is an effective one for determining the evaporation length of the jet.