Dualrail precharge logic is an effective technique to counteract differential power analysis (DPA) attacks. The key problem is to guarantee the symmetrical capacitive loads between true and false logics. A dualrail signal parallel routing method based on commercial place&routing EDA is proposed in this paper to get symmetrical capacitive loads. Firstly, the singlerail nets are routed in odd routing tracks by EDA and then dualrail wires are obtained by duplicating and moving the routed wires to the even routing tracks. As a result, each pair of dualrail signal wires has the same routing structure and capacitance. The parallel routing method is implemented in an AES (Advanced Encryption Standard) coprocessor. The experimental results indicate that the capacitances of the dualrail signal wires are perfectly balanced.