Abstract: Aiming at the islanding effect during the grid-connected operation of distributed photovoltaic power stations, a passive anti-islanding protection strategy suitable for distributed photovoltaic power stations is designed. Based on the characteristics of reliability, speed, selectivity and sensitivity of protection realy, the strategy comprehensively considers operating parameters such as the grid-connected voltage level, installed PV capacity, and circuit breaker characteristics of the grid-connected cabinet. Starting from practical applications, an integrated anti-islanding protection strategy is developed. The strategy is deployed on the hardware platform of a protection relay with STM32F407 as the main CPU. After performance testing, it has been successfully applied to the 10 kV grid-connected project of the 5 MW distributed photovoltaic power station of Xuzhou Qingchi Photovoltaic Technology Co., Ltd. Field operation results show that the anti-islanding protection strategy operates reliably and has strong practicability, which can meet the requirements for the safe and stable operation of distributed photovoltaic power stations.