Abstract: Fruit size was one of the important economic traits of fruits, which directly affected the yield, quality and commodity of crops. The growth and development process of fruit was not only affected by the inherent genetic background of crop species and varieties, but also by the environmental factors and cultivation management factors. And the influence of the former was more direct and profound. The research status of the functional genes and transcription factors related to the regulation of fruit size in horticultural plants in recent years was reviewed in this paper. And the research progress of POS1, FW, YABBY, WOX, OFP, NCED, YUC, GAox20 and AREB genes in horticultural crops such as tomato, cucumber, pear, grape, apple and citrus was emphatically introduced, which could provide theoretical reference for the future research on the regulation of fruit size.