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When the cold atom clock operates in microgravity around the near-earth orbit, its performance will be affected by the fl uctuation of magnetic field. A strategy is proposed to suppress the fl uctuation of magnetic field by additional coils, whose current is changed accordingly to compensate the magnetic fl uctuation by the linear and incremental compensation. The fl ight model of the cold atom clock is tested in a simulated orbital magnetic environment and the magnetic field fl uctuation in the Ramsey cavity is reduced from 17 nT to 2 nT, which implied the uncertainty due to the second order Zeeman shift is reduced to be less than 2×10?16. In addition, utilizing the compensation, the magnetic field in the trapping zone can be suppressed from 7.5 μT to less than 0.3 μT to meet the magnetic field requirement of polarization gradients cooling of atoms.