Abstract: Short-term high-temperature (480℃×48 h) and long-term high-temperature (400℃,2 000,4 000,6 000,8 000 h) aging tests and accelerated corrosion test at 90℃ in 2 500 mg·kg^-1 boric acid solution were performed on B₄C/Al composite plates used in spent fuel dry storage and transport cask. The aging and corrosion behavior of the composite plates were studied. The results show that the color on local surface of the composite plate became grey and the dimensions, density, mass and mechanical properties changed little after aging at 480℃ for 48 h; after aging at 400℃ for a long term, the composite plates illustrated a good stability of dimensions and a high corrosion resistance, and the decrease of mechanical properties was within the normal range of fluctuation. After immersion in the boric acid solution for over 4 000 h, a slightly localized corrosion occurred on the rectangle samples of composite plate, while the pitting corrosion of the coated samples occurred with the elongation of immersion time and became relatively obvious after immersion for 8 000 h.