The surface morphology，composition，and chemical composition of corrosion products of environmentally friendly polyester coated high aluminum zinc aluminum magnesium color coated sheets soaked in hydrochloric acid and sodium hydroxide wereanalyzed by using scanning electron microscopy and X-ray instrument. The acid alkali corrosion mechanism of environmentally friendly polyester coated high aluminum zinc aluminum magnesium color coated sheets was explored. The results showed that the coatingphase of environmentally friendly polyester coated high aluminum zinc aluminum magnesiumcolor coated sheets was continuous gray phase and rich Al phase white rich Zn phase/Zn Mg phase and black Mg₂Si phase. Corrosion in the same concentration（5%）medium（hydrochloric acid/sodium hydroxide） for 24 hours，with complete surface coating and visual inspectionwithout visible blistering. Its color loss level and light loss level met the requirements of level 0in GB/T 1766—2008；after soaking for 144 hours，the degree of foaming on the color coatedboard soaked in hydrochloric acid solution was more severe than that soaked in sodiumhydroxide solution. The reason was both the different molecular penetration abilities of thecorrosive solution medium itself and the self-protection mechanism of corrosion productcoverage inhibition. The difference lied in the corrosion products. The corrosion productssoaked in hydrochloric acid were mainly composed of ZnO and Fe，while the corrosion products soaked in sodium hydroxide were mainly composed of Al（OH）₃，Zn，and Fe. The similarity lied in the surface scanning results of the coating cross-section，which indicated that whether it was hydrochloric acid or sodium hydroxide corrosion，the white rich Zn phase/Zn Mg phase was significantly reduced，followed by the continuous gray rich Al phase.