Diaphragm material selection is the critical issue in addition to the shape or geometry optimization to improve the mechanical performance of micro-fabricated pressure sensors. Although single crystal silicon (Si), polysilicon (PolySi), graphene, Si₃N₄ and SiO₂ are the common diaphgram materials, LTCC is a good candidate for the high temperature applications. Thus, performance analysis of diaphragm is required to find optimum diaphragm size.In this study, low temperature cofired ceramic (LTCC) based circular diaphragm design was considered for the Fabry–Pérot Interferometer (FPI) pressure sensor application. Characteristics of low temperature cofired ceramic (LTCC) based circular diaphragm was analyzed by finite element method. Mechanical sensitivity, resonance frequency and static deflection of the diaphragm are the fundamental characteristic to be analysed and evaluated for MEMS sensor performance of micro electro-mechanical system (MEMS) based ltcc diaphragm.Thickness of LTCC diaphragms were selected 50 μm, 75 μm and 100 μm with the diameter of 3 mm, 4 mm and 5 mm, respectively. The performances of diaphragms are analytically studied and simulations were done using ANYS. Our results showed that sensitivity and frequency response of this structure can be designed flexibly by adjusting the parameters of the ceramic diaphragm size including radius and thickness. The key contribution of this work is to study the LTCC diaphragm with different size for future works.