The utility model relates to a wax prevention and viscosity reduction treatment device for a pipeline composite magnetic field, and is applied to wax removal of a crude oil transportation pipeline. The device is characterized in that a suspending plate is fixed between two flanges of the pipeline, the center of the suspending plate is provided with a magnetic core fixation hole, the periphery of the fixation hole is provided with crude oil channel holes, a thread fixation head at the end part of a magnetic core penetrates through the fixation hole of the suspending plate, the magnetic core is fixed on the suspending plate by a diversion nut, a center line of the magnetic core is vertical to the suspending plate, and the external of a steel pipeline corresponding to an effective magnetic course of the magnetic core is provided with a magnetic pushing high-frequency cable winding which is formed by the winding of an insulation-skin electric wire. The utility model has the effects that an axial alternating magnetic field is generated by the magnetic pushing high-frequency cable winding, the axial magnetic field with high frequency and a radial magnetic field with high frequency are mutually acted to cause the magnetic fields to swing with high frequency, the magnetic fields which swing drive media molecule to swing and reorganize, thereby an associated body formed by big molecules is caused to be damaged and dissolved, aggregation and deposit of the associated body are further prevented, the viscidity of fluid is lowered, the flowing capacity is improved, and the purposes of wax prevention and viscosity reduction are achieved.