Abstract:Agar is a linear polysaccharide extracted from the cell walls of Gracilaria algae.Its thermoreversible double-helical gel network structure endows it with favorable properties such as gelation ability，stability，and biocompatibility，making it indispensable in fields such as food，pharmaceuticals，and biomaterials. However，with the continuously increasing demands for agar quality in various applications，traditional extraction and modification methods have become inadequate. High-quality agar has thus emerged as a critical direction for industry development.This paper systematically reviewed recent strategies for the precise regulation of the molecular structure of high-quality agar，focusing on the effective modulation of agar quality，including gel properties，molecular weight，sulfate content，and the composition of 3，6-anhydrogalactose，through physical，chemical，and enzymatic modification methods during agar production. Furthermore，the influence mechanisms of polysaccharides' molecular structure on the physicochemical properties of agar were thoroughly analyzed，revealing trade-off relationships in the process of performance optimization，so as to provide theoretical insights for the innovative development of high-end functional agar gel materials.