Evapotranspiration is key to hydrological and heat transfer in the soil-plant-atmosphere continuum (SPAC). It is also an important component of water and energy balances, and now it is becoming an important research subject in meteorology, hydrology, ecology and other related areas. The temporal and spatial variations in surface evapotranspiration at the regional scale are very complicated, which means that it is still difficult to measure surface evapotranspiration at the kilometer scale above a heterogeneous underlying terrain. Remote sensing methods can provide regional evapotranspiration results by using an empirical or semi-empirical model, but the parameters in the models and the outputs need to be improved and optimized according to the real-time measurement results. The difficulty with model verification is how to obtain surface evapotranspiration at the kilometer scale. However, the development of the scintillometry method may be able to solve this problem. The scintillometry method can adapt to complex surfaces, and produces accurate results when both time and space are averaged. This method has become an effective way to measure regional evapotranspiration and may be the best way to verify the outputs of remote sensing models. This study discusses the background theory to the scintillometry method, summarizes the potential applications of the method, and analyzes the uncertainties in the hardware equipment, the environmental factors, and key parameters in the calculation. Finally, we put forward research prospects based on theoretical principle, the calculation method, and potential applications. Our summary and analysis can be used to promote the application of the scintillometry method in regional evapotranspiration measurements and relevant disciplines.