Abstract In this research, we report the theoretical study of an optical microresonator in form of hollow bottle for the measurement of hydrostatic pressure in microfluidics. The proposed device bases its operating principle on the excitation of the resonant modes WGMs that are confined to the interior of the optical cavity through the evanescent coupling of the light from the outside. The analytical study developed to determine the sensitivity of the device to changes in internal pressure in the hollow micro-bottle, is developed from a layer model with application of boundary conditions in the problem, where it is necessary to consider the excitation of the transverse modes WGMs and the elastic-optical effect produced by the internal pressurization of the resonant cavity. In the investigation we have concluded that the theoretical results present a good approximation with the experimental results using the layer model with which it is possible to optimize the design of this type of devices to improve the sensitivity for the measurement of the hydrostatic pressure in microfluidics.