This paper is aimed to investigate the actual conditions of standalone PV(Photovoltaics) streetlight in public place and analyze cause of failure and derive the method of decrease for standalone PV streetlight. The cost of installing standalone PV streetlight in a public for the safety and convenience of life is expensive(300 million won per unit). Management of standalone PV streetlight is important because it is operating system itself, after installation, but concern degree of management is very low and development of technology has not been done. Accordingly, standalone PV streetlight in public place is not operate in night, this phenomenon is lasted for several days to months. Therefore this study, for standalone PV streetlight constantly to keep the normal operation, investigation conducted to check status of standalone PV streetlight(50 units), the voltage of the main parts and analyze the cause of the failure. In addition, the improvement of standalone PV streetlight is suggested by using FTA(fault tree analysis).