Switching of the switch and the penetration of the distributed power make the topology and operation mode of a distribution network complex and changeable. This brings challenges to the faulty section of the feeder. A feeder tree fault segmentation method is proposed, which decomposes the feeder topology into two connection units of a branch and a forked zone. The state of each switch on the feeder is identified by the intelligent feeder terminal unit so that the feeder topology information is updated in real time. This is used to calculate the branch state function. The consensus fault-tolerant criterion is used to judge the reliability of the fault zone. Cross-validation is further performed in conjunction with the state of the bifurcation zone. The definition of the positive direction of the node information is based on the pre-current flow information. In this way the problem of defining the direction of the fault current of the active distribution network is solved. Finally, an example is given to verify the superiority of the proposed method. This work is supported by National Natural Science Foundation of China (No. 51777077) and Science and Technology Project of Guangdong Power Grid Company (No. GDKJXM20172882).