Different concentrations of propylene glycol alginate (PGA) were added to flour to explore the effects of PGA on flour pasting properties, dough rheology, microstructure, texture and sensory quality of steamed bread. The results showed that the gelatinization temperature of the flour increased from 58.8 ℃ to 59.5 ℃, the maximum tensile resistance increased from 518 to 597, the hardness of the dough increased, the water distribution in the dough was more uniform, and the rheological properties were better after adding PGA. The tangent value of the loss angle tanδ (G'/G") continued to increase, and finally led to increased specific volume, gloss and chewiness of the steamed bread. The experimental results showed that the quality of the steamed bread was the best when the concentration of PGA in the flour is 500~1 000 mg/L, and the excess of PGA would reduce the volume of the steamed bread and make the steamed bread taste hard. In a word, the hydrophilic and lipophilic properties of PGA make the water more evenly distributed in the dough structure, significantly affecting the operating characteristics of the dough and promoting the quality of the steamed bread.