N-lauroyl sarcosine triethanolamine reactant is a surfactant with excellent performance and good biodegradability. It is widely used in daily chemical, metal processing and hydraulic transmission media industries. The effects of reaction temperature and time on the structure of N-lauroyl sarcosine triethanolamine reactant were studied. The structure was confirmed by infrared spectroscopy and nuclear magnetic resonance. The results show that the anionic surfactant (product A) is more easily obtained at low temperature (75℃), and the nonionic surfactant (product B) is more easily obtained under high temperature (130℃). At the same time, the foam properties and hard water resistance of the two products were compared. It was found that when the mass concentration is less than 0.8%, the surface tension of the product A is smaller than the surface tension of the product B. When the mass concentration is 0.3%, the surface tension is the smallest, and the foam half-lives of product A and product B are 22.56 min and 28.26 min, respectively. When the mass concentration is 1.0%, the product B has an improved hard water resistance of 23.57% compared with the product A, which is more favorable for emulsion stability. Through the research to provide a reference for the theoretical research and practical application of N-lauroyl sarcosine triethanolamine.