The invention discloses a milling machine for a construction machinery. The lower ends of piston rods of hydraulic cylinders are welded to the middle parts of the upper end surfaces of transverse plates; vertical plates are welded on the left and right sides of the transverse plates; circular rods are rotationally mounted between the bottoms of the left and right vertical plates; driving wheels are welded on the external walls of the circular rods on the rightmost side; driving belt wheels are welded on output shafts of motors; the driving belt wheels are in transmission connection with closest driven belt wheels through belts; a pavement laser profilometer is embedded in the bottom of a machine body; and a displacement sensor and the pavement laser profilometer are both electrically connected with an operation mechanism. According to the milling machine for the construction machinery, even though a milling machine body suffers uneven pavements, the machine body can also be kept parallel to the horizontal plane so that the pavement milling quality is greatly improved; and as each driving mechanism independently performs driving, each driving mechanism can be singly adjusted withoutaffecting each other so that the adjusting efficiency is enhanced; and under the action of an anti-skid layer, the milling machine for the construction machinery is beneficial for smooth movement.