NOVELTY - A biodiesel esterification device comprises biodiesel esterification reactor comprising tank body, heating sleeve and solvent recovery unit. The biodiesel esterification reactor is provided with set of solvent recovery unit. The solvent recovery unit comprises gas phase solvent condenser provided above top of biodiesel esterification reactor. A solvent temporary storing tank is provided below the biodiesel esterification reactor. A gas phase solvent recovering tube is provided at top of tank body of biodiesel esterification reactor and connected with gas phase solvent condenser.    USE - A biodiesel esterification device.    ADVANTAGE - The device greatly reduces reaction time, solves the problem that esterification is always inexhaustive, improves production efficiency and quality, and has simple and reasonable structure, convenient manufacturing and mounting process, simple technical technologies and convenient operations.    DETAILED DESCRIPTION - A biodiesel esterification device comprises biodiesel esterification reactor comprising tank body, heating sleeve and solvent recovery unit. The biodiesel esterification reactor is provided with set of solvent recovery unit. The solvent recovery unit comprises gas phase solvent condenser provided above top of biodiesel esterification reactor. A solvent temporary storing tank is provided below the biodiesel esterification reactor. A gas phase solvent recovering tube is provided at top of tank body of biodiesel esterification reactor and connected with gas phase solvent condenser. A liquid phase solvent reflux tube is connected with gas phase solvent condenser and the solvent temporary storing tank and circulating pump connects the solvent temporary storing tank and solvent input tube of biodiesel esterification reactor. An INDEPENDENT CLAIM is included for biodiesel esterification, comprising:    (A) adding oil, reaction solvent and catalyst into biodiesel esterification reactor, infusing steam to heating sleeve to heat reactor, controlling cracking temperature of esterification in reactor at 70-95 degrees C, and agitating catalyst to catalyze and finish esterification process;    (B) controlling gas phase solvent generated during reaction to naturally introduce into solvent gas phase condenser;    (C) feeding cooled and condensed liquid phase solvent of gas phase solvent into liquid phase solvent temporary storing tank; and    (D) introducing solvent in solvent temporary storing tank in reactor, and repeating operations until esterification is complete.