从面心立方（ＦＣＣ）基体的对称性出发．我们确定了该基体内固态沉淀反应所致Ｂ２结构沉淀相之间的界面取向；基于稳定界面结构应具有最低能量的考虑，提出了几种可能的沉淀相间界面结构模型；实验观察表明，Ｎｉ－Ｂｅ合金中沉淀相（β）间界面取向满足对称性要求，β／β界面结构跟自由β相的〈１１０〉｛１１２｝孪晶界面相同，但界面附近存在应变场． Starting from the symmetry of the FCC core. We determine the interfacial orientation between the precipitated phases of the B2 structure caused by the solid state precipitation reaction in the matrix. Based on the consideration that the stable interface structure should have the lowest energy, several possible interphase structure models of precipitated phases are proposed. Experimental results show that Ni- Be alloy, the orientation of the interphase between the precipitated phases (β) satisfies the symmetry requirement. The β / β interfacial structure is the same as the <110> {112} twin interfacial phase of the free β phase, but the strain field exists near the interface.