Perovskite-based solar cell materials have attracted tremendous attentions in recent years due to their promising high energy conversion efficiency. However, during this stage of their development, there are key issues that delay commercialization, such as lead (Pb) toxicity, long-term instability, and vulnerability to structure defect and temperature changes, and many more. In this paper, first-principles are applied to analyze and optimize the electronic structure of perovskite materials with formula ABX3 by replacing the B atom- where Pb originally sits- with other nontoxic elements. The calculations of the charge densities of molecules are performed with the ABINIT software. As a result, several promising perovskite-based solar cell materials with suitable band gaps for photovoltaic productions are presented. These findings enrich the search for a suitable perovskite material to eliminate the need for toxic Pb in perovskite solar cells.