The invention discloses a method for preparing regenerative low-melting-point polyester with a waste-polyester alcoholysis method. The method includes the steps of 1), pretreatment of waste polyester;2), alcoholysis of the waste polyester; 3), quality regulation of esters and adding of one or multiple copolymers of isophthalic acid, 1-4 cyclohexane dimethyl alcohol and neopentyl glycol; 4), polycondensation and slicing preparation, wherein the low-melting-point polyester finally obtained is 0.60-0.70dl/g in intrinsic viscosity, 100-180DEG C in melting point, 3.0+/-0.3% in content of diglycoland smaller than 6 in chroma value of b. The obtained regenerative low-melting-point polyester is applicable to preparation of cationic-ion dyeable poester filaments and short fiber, and high-value recycling of the waste polyester is realized.