To address the challenge of efficient spectrum resource utilization by unmanned aerial vehicles (UAVs) in interference-prone environments, this study optimizes UAV bandwidth allocation, frequency selection, and power distribution while ensuring solution diversity and uniformity. A multi-objective optimization model for joint spectrum resource allocation is proposed, along with an enhanced multi-objective evolutionary algorithm incorporating adaptive hybrid crossover and constraint repair strategies. The developed algorithm is applied to spectrum resource allocation problems, featuring an adaptive crossover mechanism and a constraint repair strategy to guarantee solution feasibility. Experimental results demonstrate that the proposed method effectively optimizes UAV spectrum resource allocation schemes, significantly improving anti-interference performance. Furthermore, it not only maintains convergence but also enhances the diversity and feasibility of the solution population distribution.