The invention relates to a method for preparing a high-comfortable composite functional polyester fiber, comprising the steps of: first esterification reaction section, secondary esterification reaction section, polymerization reaction process and spinning process, wherein aliphatic dicarboxylic acid and/or non-centrosymmetrically aromatic dicarboxylic acid is led into the first esterification reaction section to serve as a third monomer; flexible polyethylene glycol is led into the secondary esterification reaction section to serve as a fourth monomer; after finishing the esterification reactions, hindered amine light stabilizer and hindered phenolic antioxidant which are respectively prepared by taking acetic acid and ethylene glycol as solvents and hydroxyl silicone oil are added; after finishing pre-polymerization and before final polymerization of the polymerization reaction process, ultraviolet light absorber and antistatic agent are added; and before finishing the spinning process, polyester slices are performed pre-crystallization and drying; fibers with odd-shaped cross sections of three-leaf, cross, five-leaf and the like are prepared by melt spinning. The obtained polyester fiber is anti-ultraviolet light, antistatic, anti-pilling and has wet-absorbing quick-drying performance; and the fabric has high comfort.