A suspended graphene pressure sensor which is appropriate for nano-electro-mechanical system（ NEMS） is proposed

and combined with traditional micro mechanism process technology

its fabrication process is also put forward. Raman spectra is used to represent mechanically exfoliated graphene membrane with different thickness

and the fact that the intensity of G and 2D peaks are related to membrane thickness is identified. Based on the membrane bulge test

respectively gave the relationship between maximum deflection of graphene membrane suspending on rectangle

square and circle cavity and pressure difference; meanwhile

pressure sensitivity of membrane under the three cavity shapes are calculated respectively

and it can be found that graphene membrane of single-layer graphene membrane under rectangle cavity is the most and when rectangle width

square length or circle diameter is bigger

or membrane thickness is smaller

pressure sensitivity is higher

and the calculation result shows that the pressure sensor has high sensitivity.