This study focuses on a specific problem related to the caprock deformation induced by the in-jection of CO2 at depth. The adopted methodology includes the development of a mathematical model that incorporates the deformable behaviour of storage media and the flow of two immiscible fluids (CO2 and wa-ter) within the aquifers while the surface rock or caprock layer is modelled as a thin plate. Governing equa-tions are solved for the axisymmetric flexural deflection due to a constant rate of injection of CO2. The re-sults show that this semi-analytical solution is capable of capturing the pressure build-up during the very early stage of injection, resulting in a high rate of surface uplift. The calculation time required using the semi-analytical solution is very short; it can be employed as a preliminary design tool for risk assessment using pa-rameters such as the injection rate, porosity, rock properties and geological structures. This semi-analytical solution provides a convenient way to estimate the influence of high injection rates of CO2 on the caprock de-formation. The methodology in this development can easily incorporate other pressure distributions; thus ad-vances in hydrology researches can also benefit this approach.