This paper proposes a 3- mid-infrared band polarization-independent and CMOS-compatible graphene modulator， which mainly includes two parts： the mode conversion structure and the graphene modulator. This modulator not only fulfills the requirement of compatibility with CMOS， but also can achieve polarization-independent modulation of the fundamental mode. Simulation results show that this modulator can achieve an extinction ratio（ER） higher than 20 dB in the mid-infrared band from 2.95 to 3.05 ， the insert loss for both TE and TM modes are less than 1.3 dB， and polarization-dependent loss is less than 1.09 dB. Through the calculation， the 3 dB bandwidth up to 9.47 GHz can be obtained when the length of the device is 420 .