The invention discloses a power grid islanding detection and anti-islanding protection method for a large-scale wind power generation system. The method includes the following steps that: a node type list and a node connection list are initialized; circuit breaker tripping signals in a power grid are monitored, and the node connection list is updated according to the monitored circuit breaker tripping signals, nodes corresponding to the circuit breaker tripping signals are pushed into a queue; and logical judgment is carried out according to the updated node connection list and the queue, so that whether the nodes corresponding to the circuit breaker tripping signals are islanded can be judged. The method is used for the large-scale wind power generation system and carries out islanding detection and anti-islanding protection at a high-voltage main grid of a power source side. The power grid islanding detection and anti-islanding protection method is advantageous in being fast, accurate, efficient, safe and stable. According to the power grid islanding detection and anti-islanding protection method provided by the technical scheme of the invention, line weight does not require to be considered, and therefore, anti-islanding protection actions can be performed more rapidly.