The invention discloses a degumming agent and a preparation method and application of the degumming agent. The degumming agent mainly contains the following ingredients in percentage by weight: 40%-60% of main solvent, 1.5%-3% of penetrant, 6%-10% of activating agent, 0.1%-0.3% of corrosion inhibitor, 5%-15% of thickening agent, 5%-10% of emulsifier, 10%-15% of volatilization inhibitor and the balance of water, wherein the main solvent is one or a mixture of several of methyl carbonate, ethyl-3-ethoxy propionate, dibasic ester, alkoxy alcohol, alcohol amine or benzoic alcohol. The degumming agent is simple in using method, is free from being heated and can be used at normal temperature by either brushing or spraying, and the time for washing is short, so that the production efficiency can be greatly increased.