Abstract: A boric acid solution was used to simulate the environment of actual spent fuel storage. The corrosion behaviors of Al-B₄C composite materials in boric acid solutions were investigated. The microscopic morphology was observed by SEM and EDS. The phases of samples before and after the corrosion tests were measured by XRD and the dry weight of the samples was also measured. The results show that the corrosion is caused by aluminum in the Al-B₄C composite; a dense layer of Al(OH)₃ is formed after corrosion test in boric acid solution at 0 to 500 ppm and the samples gain weight after corrosion test; an amorphous Al(OH)₃ sediments with wadding structure are found after corrosion in boric acid solution at 2 500 ppm and the samples also gain weight; some local areas appeared chapped and the corroded pits can be observed after corrosion in boric solution at 10 000 to 25 000 ppm and the samples lost weight. The corrosion resistance decreases with the increasing of concentration of boric acid. In order to improve the corrosion resistance, it is necessary to make a surface protection on Al-B₄C composite.