Oil-in-water （O/W） emulsion was prepared by ultrasonic emulsification with high acyl gellan gum（HA）and low acyl gellan gum（LA） as emulsifiers and medium-chain triglyceride（MCT） as oil phase. Compared with Arabic gum （GA）， the emulsifying properties of high and low acyl gellan gum were compared. The appearance change， interfacial tension， Zeta-potential and particle size distribution of emulsion with different concentrations and types of gellan gum were investigated. The results showed that the average particle size of O/W emulsion prepared with HA as emulsifier was slightly larger than that prepared with GA， while the particle size of LA emulsion was the largest. The absolute value of Zeta-potential of HA emulsion was significantly larger than GA emulsion（P<0.05）， and the interfacial tension of HA emulsion was smaller than GA emulsion under the optimal concentration condition， so the emulsifying stability of HA emulsion was better than GA emulsion. LA emulsion has the smallest absolute value of Zeta-potential， the largest interfacial tension， and the worst emulsion stability. The storage test showed that the stability of HA emulsion was higher than GA emulsion， and the particle size change rate at 60 ℃ was significantly lower than GA emulsion. LA emulsion is extremely unstable， and stratification occurs on the day of preparation. In this paper， the application differences of different acyl gellan gum in emulsifying properties were studied. The results showed that high acyl gellan gum had good emulsifying activity and stability， which provided important significance for the quality improvement and application promotion.