The invention relates to a composite emulsifier and use thereof in steamed food made of fermented frozen dough. In the invention, the combined use of ssl-csl, triglycerol stearate, glyceryl monostearate and sucrose ester improves the frozen cracking condition of the frozen dough to a certain extent, and improves the flavor and internal structure of finished steamed bread made of the frozen dough to a certain extent. The addition amount of the emulsifier for a minimum frozen cracking rate of the dough consists of 0.2 percent of ssl-csl, 0.3 percent of triglycerol stearate, 0.3 percent of glyceryl monostearate and 0.4 percent of sucrose ester.