The invention belongs to the field of screw pump oil extraction equipment and particularly relates to a screw pump direct drive device with a brake device being arranged on the top. The screw pump direct drive device with the brake device being arranged on the top comprises a motor, the brake device and a well plugging device, wherein the motor, the brake device and the well plugging device are connected in series in the vertical direction. A polish rod connected with a downhole screw pump penetrates through the middle portions of the motor, the brake device and the well plugging device. The brake device, the motor and the well pulling device are sequentially connected through flanges from top to bottom. The brake device structurally comprises an upper shell, a lower shell, a pump wheel, an upper main shaft, a lower main shaft, a shaft sleeve and a protective cover. The bottom of the protective cover is connected to the well plugging device through a flange and is fixedly connected to the top of the protective cover at the same time. The space between the upper shell and the lower shell is filled with heat transfer oil. The upper main shaft is installed at the center of the upper shell and the center of the lower shell through bearings. The screw pump direct drive device with the brake device being arranged on the top conducts direct brake through hydraulic force and avoids hydraulic brake, and the screw pump direct drive device with the brake device being arranged on the top has the advantages of being simple in movement mechanism and reliable in action and almost avoiding wear; and in this way, the reliability of the brake mechanism is greatly improved, and the service life of the brake mechanism is greatly prolonged.