The invention discloses an esterification modification method for wood fiber biomasses, comprising the following steps of: firstly, pretreating wood fiber biomasses, i.e. drying and smashing; carrying out pre-ball milling; adding esterification reagent, and continuously carrying out ball milling to carry out an esterification modification reaction; and washing and drying products after the reaction to obtain the esterified modified products of the wood fiber biomasses. According to the method, various wood fiber biomasses are taken as raw materials, wide in source, low in cost, and high in resource utilization rate, and the conventional mode of the single modified cellulose can be changed; and the wood fiber biomasses are esterified in the process of ball milling, the esterification reaction can be carried out within a dissolved homogeneous system or a heterogeneous system in which the solvent is dispersion medium, and the esterification modification method is simple in modifying technology, environment-friendly, and free from the generation of 'the three wastes', and does not need recover the solvent. The infrared and weighing method result shows that the product is good in esterification effect, very good in practical applicability, and better in economic prospect.