Active shield is a sensor mesh which devised and implemented on top of most secure chips or in secure embedded system as a good protection for circuits and sensitive data stored in the chips.It is one of the most effective annoyances to microprobing attackers.But shield rerouting attack can defeat active shield by disclosing the geometry structure of the shield,causing a short circuit of the sensor mesh.This paper proposes a dynamic active shield to resist shield rerouting attack.The dynamic active shield is a sensor mesh contains some routing nodes and connecting metal lines between adjacent nodes.Change the connection statuses of routing nodes result in different paths of the shield sensor mesh.The dynamic active shield increases the security of the circuits and defeats the shield rerouting attack by changing the path of the sensor mesh every few clock cycles,makes it more difficult to distinguish the geometry structure of the top layer sensor mesh of the shield.At last,we analyze the area and power consumption of the dynamic active shield.