To meet the test requirements of interior ballistic pressure parameters of small-caliber artillery, a small capacitor high pressure sensor was developed. The design thought of the mechanical part of capacitor high pressure sensor was introduced and the detail of calculation process was listed. The transient analysis and static analysis were respectively made for the case and the cover respectively with large-scale finite element analysis software ANSYS, the dynamic response of the case and the static response of the cover were got. The result shows that this design meets intensity requirement and it provides basis for the test circuit design.