The scarcity of spectrum resources and the broadcast nature of wireless channels pose severe challenges to the security of UAV-assisted communication systems. Traditional physical layer security(PLS) schemes rely on artificial noise to enhance security, but the resulting co-channel interference can degrade the system’s secrecy transmission rate. This paper proposes a PLS communication scheme based on co-channel interference coordination, where co-channel interference arising from spectrum reuse replaces artificial noise to interfere with eavesdroppers while reducing interference to legitimate users. In this scheme, when the transmitter sends signals to legitimate users, power allocation and phase configuration are jointly optimized. A convex optimization model is constructed to achieve interference coordination by aiming at the phase cancellation of interference at the legitimate users, and under power constraints, the Lagrange dual method is used to derive the optimal power allocation strategy to maximize the system’s secrecy transmission rate. Simulation results show that under both static and dynamic scenarios, the user SINR exceeds 30 dB and the secrecy capacity C surpasses 10 bit/Hz, ensuring low interference to users while maintaining communication security.