The invention belongs to the technical field of organic chemistry, and particularly relates to a method for preparing a C2-C11 organic acid by taking tung oil as a raw material, which comprises the following steps: dissolving natural tung oil into a solvent of 0-20 DEG C; adding a stable free radical-type compound polymerization inhibitor accounting for 0.5-3 percent of the weight of the tung oil and an oxidation catalyst; then, enabling the temperature to rise to 80-100 DEG C; simultaneously, carrying out oxicracking on hydrogen peroxide or peracetic acid, oxygen or ozone to obtain a mixed product; and then, carrying out hot water extraction, reduced pressure distillation or rectification to obtain binary organic acids, such as an azelaic acid, a propandioic acid, an oxalic acid, an undecendioic acid and the like of which the yield is 50-85 percent and unitary organic acids, such as an n-nonanoic acid, a caproic acid, a valeric acid, a propionic acid and the like. The method for preparing the C2-C11 organic acid by taking tung oil as the raw material has the characteristics of simple operation, no environmental pollution, high comprehensive yield of the organic acids, and is suitable for large-scale industrial production for exploiting and utilizing tung oil renewable resources.