The invention provides a processing method and solution for the chemical polishing of a zinc alloy. The method comprises the following steps: a, pretreatment, namely degreasing and cleaning a zinc alloy workpiece; b, chemical polishing, namely dipping the degreased and cleaned zinc alloy workpiece into chemical polishing solution; and c, posttreatment, namely performing cleaning and drying treatment after the polishing is finished, wherein the chemical polishing solution takes water as solvent, and mainly comprises nitric acid, phosphonic acid, sulphuric acid and thiourea; the chemical polishing solution is prepared by mixing ordinary acids and organic substances, thus the components are simple and convenient to control, and the polishing effect is good; and the chemical polishing solution can be matched with other chemical treatment links.