Aiming at the problems of complex structure and high failure rate of traditional top drive rigs， a new top drive system suitable for 4000m drilling rigs was developed. The new top drive uses a permanent magnet synchronous motor to drive spindle rotary drilling directly， and the water cooling technology is used for motor cooling. Compared with the traditional top drive， the new top drive lays out the hydraulic station on the ground， while eliminating the gearbox， lubrication pump station， cooling fan and other components at the same time， so that the number of parts reduced by more than 45% The lifting ring is directly connected with the motor housing， and the main bearing is placed inside the motor rotor， which reduces the size of the top drive and reduces the number of main loaders.The guide rail structure has been optimized to improve the convenience of operation. The new top drive has the advantages of simple structure and low failure rate. It has been applied in more than 20 wells in the field， which has verified its reliability and increased the operation efficiency. The new top drive can be widely used in oil and gas drilling and workover， geological exploration， shale gas and coal seam exploration and other fields， and has a good market application prospect.