The sensitivity coefficient of sandwich PVDF pressure gauge is studied through a series of calibration experiments by using SHPB apparatus, effects of thickness and lap joint style of conducting wire and area of sensitive element to the sensitivity coefficient are discussed. Based on the test results and discussion, improvement measures are applied to improve the linearity and decrease the discreteness of sensitivity coefficient of sandwich PVDF pressure gauge. According to the tests, the fitted sensitivity coefficient is 32.9 pC/N. However, the sensitivity coefficient is affected by many factors, it is recommended that the gauge should be calibrated in the pressure range which is compatible with the actual working conditions. To facilitate calibration, a vertical Hopkinson pressure bar apparatus which could effectively calibrate PVDF pressure gauge in a limited pressure range (10～160 MPa) is designed and performed.