The invention relates to a small Lambert target energy flux density measurement meter, which comprises a main body part, a supporting part and a transmission part. The main body part consists of a small Lambert target and an energy flux meter; the supporting part consists of an aluminum profile framework, a lead screw mounting seat, a lead screw supporting seat, three support seats, three upper bearing support seats, three lower bearing support seats, a base cross beam, three base longitudinal beams, two boundary beams, a motor mounting seat, a slide rail and a slide block; and the transmission part consists of a lead screw, a shaft coupling, a stepping motor, a speed reducer, gear mandrels, two pinions and a rack wheel. The small Lambert target is driven to move upwards and downwards in a manner that the rack wheel (32) and the two pinions are driven to transfer power to the lead screw (15) through the stepping motor (24) and the speed reducer (25). The energy flux meter (14) is mounted on the aluminum profile framework (11) so as to measure the energy flux density value of a coordinate position.