Abstract:In this study the Smilacina atropurpurea was used as material，extracted of soluble substances from Smilacina atropurpurea of ultrasound-assisted，the effect of the amount of the drying agent，the concentration of the material，the feed rate and the inlet air temperature on the powder extraction rate during the spray drying process，study the optimum spray drying process conditions were investigated by orthogonal test，and the spray drying powder was discussed.Antioxidant activity analysis was performed.Studies have shown that when the amount of dry agent added was 7 g/100 mL，the concentration of concentrated liquid was 10%，the inlet air temperature was 220℃，and the feed rate was 14 mL/min，the powder extraction rate 29.87%.In the analysis of antioxidant activity，it was found to have a good free radical scavenging effect，and the clearance rates of DPPH free radicals，hydroxyl radicals and ABTS+radicals all increased with the increase of sample concentration.