China’s medium-low yield fields are widely distributed and have great potential for land productivity improvement. Improving the land productivity of medium-low yield fields is of great significance for ensuring food security and achieving sustainable development goals (SDGs). Assessing the quality and spatial distribution of medium-low yield fields is the prerequisite and basis for land improvement. This paper systematically reviewed the concept, evaluation indicators, and main assessment approaches of medium-low yield fields. The main problems and development trends of the assessment of medium-low yield fields in China are also discussed. The existing concepts of medium-low yield fields focus on quantity and quality, and there are few studies on ecological indicators and sustainable development abilities. The indicators system and assessment approaches are not uniform and the temporal and spatial variation of low- and medium-yielding fields is unclear. In the future, the medium-low yield fields assessment should consider quantity, quality, and ecology indicators. The medium-low yield fields assessment should be focused on the multi-scale assessment indices system construction, multi-source data fusion, assessment methods innovation, and determining the spatial and temporal change in multi scales. It is helpful to explore ways to increase the productivity of green, high-yield, and efficient agricultural production, ensure food security and promote the realization of SDGs.