A new type of motor drive wheel traction device is proposed,the structure and principle of the traction device is elaborated.The parameter calculation model is established to calculate the relevant parameters and analyze the obstacle-surmounting ability of traction device.The changes relationship of each parameter is verified and calculated.The traction device is desirable in stability and meshing of actuator and flexible in control of the tractor.The stability,carrying capacity and wellbore adaptability of the tractor in down-hole driver are improved.In addition,it can be enhance the flexible bending adaptability and over-obstacle capacity of tractor in down-hole operation.It can be provides a new idea for designing and development of down-hole traction device in the oil and gas well areas.