Abstract: Enlightened by biological immune system, this paper applies the idea of vaccine extraction and vaccination, this paper proposes quantum-behaved particle swarm optimization with immunity algorithm (IQPSO). In this algorithm, vaccination can guide the particles to evolve towards much better direction. Experiments show that attribute reduction based on IQPSO algorithm achieve much better result both in convergence speed and optimization capabilities in comparison with other algorithms, such as Hu algorithm, particle swarm optimization, and quantum-behaved particle swarm optimization.