Due to the influence of climate change and human activities, slope water yield characteristics have changed, and the “activity” of water has begun to weaken, resulting in slope ecological degradation and river runoff attenuation. To carry out refined water system management and delay environmental degradation in the basin, it is necessary to accurately identify the slope water yield process and formulate the basin water yield baseline (BWYB) scientifically and reasonably. Based on bibliometric analysis and literature research methods, this paper systematically reviews the monitoring methods and monitoring elements of the water yield process in watersheds and slopes, expounds on the slope water yield process identification method, and also discusses the BWYB threshold and the control measures of slope water yield. Through a comprehensive analysis of the BWYB and a summary of the observation technologies for the water yield process, this paper offers a significant reference and basis for establishing a monitoring system for the evolution and regulation of basin hydrology, as well as for simulating and predicting basin water yield across various spatial and temporal scales.