Interfacial adsorption process is the initial step or key step for most of environmental micro-interface reactions. The online study of environmental micro-interfacial adsorption by in situ research methods provides direct information about interface reactions and reliable evidence for the detection of reaction mechanisms which are of great importance to understand the rule of transformation and distribution of pollutants in the environment. Because of its unique sampling principle, convenient sample pre-treatment and wide applicability, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) is becoming a powerful tool for investigating the interface reactions. Based on a brief introduction of the working principle of ATR-FTIR, the application of this technique in the investigation of adsorption on environmental interfaces, especially mineral-water interfaces, is summarized. Furthermore, the perspective of this method is discussed as well.