To study spectrum allocation problem in Cognitive Wireless Mesh Network (CWMN), an immune-based multi-objective optimization algorithm was proposed. The problem was modeled as a multi-objective optimization problem to maximize total bandwidth and minimize the total number of occupied spectra. Antibody encoding, whole cloning operator and non-dominated anti-body selection operator that are suitable for solving the problem were designed. The simulations results show that the proposed algorithm can obtain the Pareto optimal solutions of CWMN spectrum allocation, which improves the total bandwidth and minimizes the occupied spectra, so it optimizes the spectrum allocation performance.