Power quality disturbing signals is an important issue in power quality research. To locate the power quality disturbing in power system rapidly and precisely becomes the precondition of analyzing and compensating. And correlation algorithm is effective in weak signal detecting. Its algorithm is simple and it can be made with no complicated components, especially for its capability in filtering noise, making it the most spreading useful tool in signal analyzing. This paper proposed a new method to locate power quality signals based on correlation algorithm. It can locate the starting and ending of power quality signals effectively. Through comparing several locating method, the effectiveness of the method can be proved.