Traditional silicon piezoresistive pressure sensors have disadvantages such as susceptibility to temperature, poor fracture toughness and limited sensing nodes. Therefore, a graphene pressure sensor with the suspended array structure was designed in this paper. First of all, the structure and the principle of the sensor were analyzed, and then the strain effect on the band gap of graphene was studied. Finally, the pressure amplification model and the deflection amplification model of the roof-pillar structure were established. The theoretical and simulation results showed that the pressure amplification coefficient and the radius ratio met the negative exponential relationship. Specifically, as the radius of the pillar continued to decrease, the amplification coefficient tended to a constant value. In the concentrated pressure model, the maximum deflection and the radius ratio approximately satisfied the linear relationship, and the maximum deflection had a one-third power relationship with the pressure.