Abstract: Grain weight is one of the important factors that determine the yield per plant of rice. Over the last two decades, researches on rice grain weight and grain size have been continuously boosting by molecular biological and genetic methods. Until now, multiple complicated signaling pathways have been well revealed. These studies focusing on rice grain weight have largely expanded the understanding of the dynamics of the cell division, differentiation and filling rate during certain spatially period of rice seed development. A large number of genes related to rice grain weight determination heretofore have been cloned and identified, including ubiquitination pathway, G-protein coupled pathway, hormone regulation pathway, photosynthesis regulation pathway, epigenetic regulation pathway and micro RNA regulation pathway. This review integrates recent advances on multiple signaling pathways and factors which involve in regulating rice grain weight and analyzes several successful cases using modern gene-editing technologies, subsequently offers a prospect for the"4.0 era" of biological breeding by combining various artificial intelligence technologies, big data and newly developed automatic and unmanned technologies as well as efficient environment, water and soil control technologies to significantly improve the grain weight, quality and resistance of rice. Finally, based on smart agriculture, we propose the future development direction of promoting the high-quality development of China's agriculture and the rural revitalization by combining the supporting technologies with modern molecular biology, genetics and bioinformatics to realize the objective from theory to application.