It installed the monitoring devices with a certain distance in the 35 KV line to determine accurately the fault location in this paper, the load units were grounded with taking into account the actual operating conditions of load by the ATP simulation. It found that the transient power waveforms of healthy section were very similar in the same side of fault point by the simulation, while the similarity of fault section was poor in the both sides of fault point. So the correlation coefficient was introduced to evaluate the relationship, when the similarity is high, the value of correlation coefficient is larger, on the contrary, the value of correlation coefficient is smaller when the similarity is low. Therefore, it can compare the value calculated with the threshold value preset of main station to determine accurately the fault location. The principle of this method is simple, and the data uploaded is small, so it is convenient to determine quickly the fault location.