In response to the "Carbon Peak" and "Carbon Neutrality" initiatives, the National Energy Administration issued the "Notice on launching a national distributed photovoltaic pilot program", and distributed photovoltaic power stations have been booming. This paper designs a 600 kW distributed rooftop photovoltaic system, including the calculation and selection of photovoltaic modules, photovoltaic combination boxes, DC distribution cabinets, grid-connected inverters and other balance of system. The photovoltaic system consists of 1500 photovoltaic modules, 18 junction boxes, 6 DC power distribution cabinets, 6 grid-connected inverters and balance of system. The system finally connects to the 380V power grid at the user side.