Abstract: The function of Ca₃N₂ on the reaction between B₄C and NH₄Cl was investigated.Under normal pressure and high temperature. The results showed that there was small amount of hBN formed in the reaction at 950℃, and little change took place after Ca₃N₂ was added. The amount of hBN achieved from the reaction at 1200℃ was more than that at 950℃, and much more hBN was gained after adding Ca₃N₂. It was concluded that Ca₃N₂ performed catalytic function in the formation of hBN. In addition, the results also indicated that the catalytic function of Ca₃N₂ was less ho that of Li₃N, and they could only act as catalyst at melting state.