NOVELTY - Preparing rosin methyl ester and biodiesel composition from turpentine, comprises (i) mixing turpentine and turpentine oil, filtering, heating, and melting to obtain turpentine liquid; (ii) adding turpentine liquid and methanol, filling, and performing esterification, disproportionation, heterogeneous, hydration, and cleavage reactions; (iii) cooling, and discharging oil phase; (iv) oxidizing alcoholic phase, performing atmospheric distillation, and recovering methanol; (V) performing atmospheric distillation by adding the oil phase, recovering methanol, collecting the product.    USE - The method is useful for preparing rosin methyl ester and biodiesel composition from turpentine.    ADVANTAGE - The method has simple production process; and is environmental-friendly, and economical.    DETAILED DESCRIPTION - Preparing rosin methyl ester and biodiesel composition from turpentine, comprises (i) mixing turpentine and turpentine oil according to the mass ratio of 1: 0.4-1.2, filtering, heating, and melting at 85-97 degrees C, and obtaining the filtrate containing turpentine liquid; (ii) adding turpentine liquid and methanol according to the mass ratio of 1:0.05-0.5 to a high voltage kettle, then filling with carbon-dioxide as a solvent without adding any catalyst under supercritical or sub-critical reaction state, at a pressure of 0-4 MPa, then performing esterification, disproportionation, heterogeneous, hydration, and cleavage reactions; (iii) cooling the reaction product and obtaining an oil phase at room temperature, discharging, allowing the oil phase to stand to divide into layers, where the upper layer is an alcoholic phase layer and the lower is oil phase; (iv) oxidizing the alcoholic phase, performing atmospheric distillation, and recovering methanol; (V) firstly performing atmospheric distillation by adding the oil phase, and recovering methanol, and passing carbon-dioxide active gas or vapor during vacuum distillation, then collecting the fraction at 200-260 degrees C containing biodiesel composition, and remaining component of rosin methyl ester.