Abstract: This paper reviewed the latest 10 years',especially the latest 5 years',advances in research on rainfed crop yield gaps from the respects of the size of yield gap between average and rainfed potential yields,yield gap explaining factors and possible methods regarding reducing the gap.The definitions and measurements of water-limited yield potential,average yield,and yield gap were also summarized.In addition,yield potentials and yield gaps at the cropping system level released from the latest research were also introduced in this paper.According to the different methods used to measure yield potential,the yield gaps can be grouped to model-based yield gap,experiment-based yield gap,and farmer-based yield gap.The cropping system yield potential was defined as the output from the combination of crops that gives the highest energy yield per unit of land and time,and the copping system yield gap as the difference between actual energy yield of an existing cropping system and the cropping system yield potential.Yield gap explaining factors were grouped into five main categories,comprising the climate factors,the edaphic factors,the crop and farm management factors,the farm characteristics and the socio-economic factors.There are three broad areas for closing yield gap in rainfed grain crops in the future and they are breeding,genetics and physiology,tactical managements including decisions of cultivar,sowing date,planting population,fertilizer rates,weed,and pest control methods etc.,strategic management revolving around soil improvement (such as amelioration of acidity,soil compaction and low SOC).There is still substantial room (from about 0.5 to over 5 t ha^-1) to increase the average yield of crops in rainfed systems in both developed and developing regions.In the future,a subsequent study of crop yield gap should focus on the multi-model ensembles of yield gap analysis,climate-pattern based yield gap analysis,and yield gaps at the cropping system level.