This paper addresses the challenge of co-optimizing anti-jamming and secure communication in UAV communications. We propose an anti-jamming secure communication scheme that integrates smart antennas with dynamic spectrum sharing. By adaptively forming beams to suppress interference, combined with space-time dual-domain information protection technology, low probability of interception (LPI) transmission is achieved. Simulations show that this scheme significantly reduces the probability of interception, effectively improves spectral efficiency and signal-to-interference-plus-noise ratio (SINR), outperforming traditional methods. The research results provide theoretical support and practical references for UAV communication and anti-jamming network deployment. This technical approach can be extended to high-security requirement scenarios such as aerial reconnaissance and satellite communications.