The invention discloses a method for producing tung oil polyhydric alcohol and byproduct glycerinum. The method comprises the following steps: (1) mixing tung oil, methyl alcohol and a base catalyst at a ratio and then adding the mixture into a high pressure kettle, performing tung oil methyl esterification reaction and separating the glycerinum at lower layer after reacting, thereby acquiring tung oil methyl ester; (2) mixing tung oil methyl ester with carboxylic acid, an acid catalyst, a hydroxylation reagent and deionized water at a ratio, increasing temperature to 35-45 DEG C, dropwise adding a hydrogen peroxide solution while stirring, controlling the dropping rate, keeping the reaction at 40-65 DEG C, and after ending the dropping, keeping the reaction temperature for 3-5h; and (3) after ending the reaction, standing and layering, separating a water phase, neutralizing an oil phase, washing with water, reducing pressure and distilling, thereby acquiring the tung oil polyhydric alcohol. According to the invention, the characteristic that the conjugated double bond of the tung oil can promote the reaction activity of epoxy groups is utilized, the tung oil methyl esterification reaction is performed at first, the glycerinum is separated, and then the tung oil methyl ester is used as a raw material for preparing the tung oil polyhydric alcohol, the hydroxylation reagent is added in the epoxidation process, cross-linking side effect can be effectively avoided and the economical efficiency of the whole process is greatly increased.