The invention discloses bleaching liquid for dacron fabric and a bleaching method of the dacron fabric. The bleaching liquid for the dacron fabric is composed of the following components by mass: 0.2-0.6 part of potassium borate, 0.5-1.5 parts of diethylene triamine penta (Methylene Phosphonic Acid) pentasodium salt, 0.5-1.5 parts of crylic acid maleic acid copolymer, 0.5-1.5 parts of 1,5-Anhydro-D-glucitol, 1-3 parts of 4-(2-nonanoyl acyloxy ethoxylated carbonyl tempol) benzene sulfonic acid sodium salt, 0.2-0.6 part of tetra acetyl ethylene diamine, 1.5-7.5 parts of sodium hydroxide, 2-8 parts of hydrogen peroxide and 1000 parts of water. When the bleaching liquid is used for bleaching the dacron fabric, the bleaching process is simple, the bleaching liquid is suitable for mass production, damage to the fabric is small, a bleaching effect is good, and breakage of the fabric can be effectively restrained.