The cellular membrane serves as a pivotal barrier in regulating intra- and extracellular matter exchange. Disruption of this barrier through pulsed electric fields (PEFs) induces the transmembrane transport of ions and molecules, creating a concentration gradient that subsequently results in the imbalance of cellular osmolality. In this study, a multiphysics model was developed to simulate the electromechanical response of cells exposed to microsecond pulsed electric fields ($\mu$sPEFs). Within the proposed model, the diffusion coefficient of the cellular membrane for various ions was adjusted based on electropore density. Cellular osmolality was governed and described using Van’t Hoff theory, subsequently converted to loop stress to dynamically represent the cell swelling process. Validation of the model was conducted through a hypotonic experiment and simulation at 200?mOsm/kg, revealing a 14.2% increase in the cell’s equivalent radius, thereby confirming the feasibility of the cell mechanical model. With the transmembrane transport of ions induced by the applied $\mu$sPEF, the hoop stress acting on the cellular membrane reached 179.95?Pa, and the cell equivalent radius increased by 11.0% when the extra-cellular medium was supplied with normal saline. The multiphysics model established in this study accurately predicts the dynamic changes in cell volume resulting from osmotic imbalance induced by PEF action. This model holds theoretical significance, offering valuable references for research on drug delivery and tumor microenvironment modulation.