Bio-based plasticizer as well as preparation method and application thereof

The invention discloses a bio-based plasticizer as well as a preparation method and application thereof, and relates to the technical field of plasticizers. The bio-based plasticizer is prepared from the following components in percentage by mass: 35 to 65 parts of bio-based dibasic acid, 30 to 60 parts of bio-based dihydric alcohol, 5 to 7 parts of a terminating agent, 0.3 to 0.9 part of an antioxidant, 0.004 to 0.006 part of a catalyst and 0.04 to 0.08 part of an auxiliary agent, the bio-based binary acid is prepared by the following steps: adding vegetable oleic acid, acid anhydride and a catalyst into a reactor, controlling the temperature to be 120-140 DEG C, finishing the reaction when the acid value is not reduced any more, cooling to room temperature, and filtering to obtain the bio-based binary acid, wherein the molar ratio of the vegetable oleic acid to the acid anhydride is 1: (2-4), and the addition amount of the catalyst is 0.6-0.9 part of the total mass of the vegetable oleic acid and the acid a