Abstract: Photovoltaic technology can convert inexhaustible clean solar energy into electrical energy, so its large-scale application is a significant way to realize the transformation of our energy structure. Photovoltaics have undergone more than sixty years of development, and different kinds of solar cells have emerged so far. Although silicon solar cells have always occupied a dominant position in photovoltaic market, it is now becoming more and more difficult to further reduce costs. New thin-film solar cells have the advantages of low cost, high efficiency, and suitability for multi-scenario applications, so they have broad prospects and have received more attention. Typically, copper-zinc-tin-sulfur-selenium (CZTSSe) solar cells have become a potential competitor among the new generation thin-film cells, due to their excellent photoelectric properties and low-cost, plentiful raw material resources. In this review we will focus on CZTSSe solar cells and describe the principle of their operation, current research, and future development prospects.