In food industry， emulsifiers are commonly used to control the physical properties and processing properties of plastic fats， where glyceride monostearate （GMS） is widely used as emulsifier. The effects of GMS （1%， 2% and 4%） on SFC， hardness， and microstructure of palm stearin were investigated at different temperatures， respectively. It was observed that SFC and hardness of palm stearin with/without GMS remarkably decreased with the increase of temperature. The influence of GMS on SFC of palm stearin was more obvious at higher temperature （21.1-33.3 ℃）， and when the amount of GMS in palm stearin was higher than 1%， SFC of palm stearin increased as the concentration of GMS increasing. When the temperature ranged from 15 ℃ to 30 ℃， the hardness of palm stearin containing 4% GMS was significantly higher than those of the other samples， and more small fat crystal and denser crystal network was formed. The results showed that when the temperature was higher than 30 ℃， the addition of GMS could increase SFC and hardness of palm stearin， and reduce the size of fat crystals to form a denser network， which provides an effective basis for the storage， transportation and quality improvement of palm stearin-based plastic fats in higher temperature season.