The invention relates to norcantharidin esterified derivatives and a preparation method thereof. The norcantharidin esterified derivatives are 7-oxabicyclo[2,2,1] heptane-2 carboxylic acid butyl ester-3 carboxylic acid butyl ester, 7-oxabicyclo[2,2,1] heptane-2,3 dicarboxylic acid hexyl ester, 7-oxabicyclo[2,2,1] heptane-2,3 dicarboxylic acid monooctyl ester, 7-oxabicyclo[2,2,1] heptane-2,3 dicarboxylic acid decyl ester, and 7-oxabicyclo[2,2,1] heptane-2,3 dicarboxylic acid dodecyl ester. The preparation method comprises the following steps: adding a corresponding alcohol in a mixing amount, adding norcantharidin and sulfuric acid in a mixing amount, mixing, stirring and heating the mixture, refluxing the mixture at 45 to 100 DEG C for 60 to 300 minutes, and obtaining oily liquid after reactions are finished; and washing the products with cold water, filtering solution obtained to obtain white waxy solid, adding preheated normal hexane in the white waxy solid to dissolve the white waxy solid, freezing obtained solution at the temperature of between 18 DEG C below zero and 4 DEG C for refrigeration and crystallization for 1 to 24 hours, and filtering the solution to obtain crystals, namely the corresponding norcantharidin esterified derivatives.