Perovskite solar cells (PSCs) have emerged as promising candidates for next-generation photovoltaic technology due to their high efficiency and low manufacturing cost. Tandem solar cells, which use different materials to capture a broader spectrum of sunlight, have even more potential for efficiency improvement. This study uses the Generalized Photovoltaic Device Model (GPVDM) software to simulate tandem silicon (Si) perovskite solar cells in order to analyse their performance and optimize their design. The simulation involves combining a silicon bottom cell and a perovskite top cell to form a tandem structure. GPVDM software allows for the modelling of a variety of parameters, including material properties, device structure, and operating conditions. By adjusting these parameters, the performance of tandem Si perovskite solar cells can be investigated under various scenarios, such as changes in layer thickness, doping concentrations, and interface properties. The simulation results reveal information about the electrical characteristics, such as the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and power conversion efficiency. Additionally, optical simulations allow for the assessment of light absorption and spectral response across the solar spectrum. The analysis of device performance under various lighting conditions and temperature variations provides useful information for optimizing the design and increasing overall efficiency. The results of this simulation study contribute to ongoing research efforts aimed at improving tandem solar cell technology. Researchers can speed up the development of efficient and cost-effective Si perovskite tandem solar cells for renewable energy applications by utilizing GPVDM software for accurate device modelling and performance prediction.