Force/strain sensitivity and fringe contrast are important parameters of spheroidal Fabry-Perot interferometers (FPIs). A static structural model and a ray optics model are proposed in this paper for analyses of force/strain sensitivity and fringe contrast. The models proposed show that the sensitivity and fringe contrast of FPIs with spheroidal cavities can be controlled through the dimensions of the spheroids. To corroborate the analyses, three spheroidal FPIs are fabricated via a chemical etching method and static force experiments are carried out. The maximum relative errors of force sensitivity and fringe contrast are 5.2% and -6.4%, respectively. We believe that this research will contribute to improvements in the performance of spheroidal FPIs.