The pattern of the front electrode and the solar cell size has a significant influence on the performance of solar cells. In order to improve the conversion efficiency of solar cells, we present a combined finite-element-genetic algorithm (GA) method for designing the front electrode and solar cell size. In the proposed method, a solar cell is considered to consist of many small unit cells, and these unit cells can well describe the current density and voltage distribution of the solar cell. In the GA, each individual represents a solar cell with a particular size and operates at a particular voltage. The validity of the proposed method is tested on the front electrode and solar cell size design problem of the side-contact and gridded cells. Two existing optimization methods are also used to optimize the front electrode and solar cell size of the two kinds of solar cells. Based on solar cells of different sizes, different optimization results are obtained using either of the two existing optimization methods. The unique optimization result can be obtained using the proposed method, and the optimization result is better than that obtained using the two existing optimization methods.