The invention discloses a microalgae biodiesel production device. The device comprises an oil extraction tank (1), a rectification tank A (2), an esterification tank (5) and a separator (6), wherein an ultrasonic generator (13) is arranged above the oil extraction tank (1), the lower side of the ultrasonic generator (13) is connected with an ultrasonic oscillation rod (14), the bottom end of the oil extraction tank (1) is connected with the middle-lower section of the rectification tank A (2), the top of the rectification tank A (2) is connected with a condenser A (3), the lower end of the condenser A (3) is connected with a solvent recovery tank (4), the bottom of the rectification tank A (2) is connected with the esterification tank (5) through a liquid pump B (16), the bottom of the esterification tank (5) is connected with the separator (6), the bottom end of the separator (6) is connected with a glycerin collector (10) and a feeding port of a rectification tank B (8), and the bottom end of the rectification tank B (8) is connected with a biodiesel collection tank (11). The device has the advantages that energy consumption is low, the structure is simple, reaction time is short, the microalgae oil extraction rate is high, the biodiesel yield is high, the purity is high, and the like.