Contraposing to all kinds of distributed energy and load characteristic in active distribution network, this paper establishes a three-stage model of the operational risk analysis in accordance with the time. In this paper, a quick uncertain power flow calculation is completed with joint possibilisticprobabilistic uncertain model based on evidence theory. According to the out-of-limit problems in results, an operation risk analysis system is established considering the power loss. The buses and branches in risk can be located by improved IEEE 33 distribution system model simulation and verifying the necessity of the joint uncertain power flow calculation model and the efficiency of the algorithm. And based on the establishment of the active distribution network security region, excogitate possible guidance of the risk control.