Electronic structure study of molecules containing B and Be is a useful tool to understand avoiding B interference in measuring ~(10)Be with a small accelerator mass spectrametry (AMS) system. In this paper, the electronic structures of BF(~1∑~+)，BeF~(~2∑~+), HBO(~1A'), HBeO (~2∑~+)，HBeF(~1∑~+)，BBeB(~1A_1)，H_2BO(~2B_2)和H_3BO(~1A'),BF~- (~2 ∏)，BeF~- (~1∑~+)，HBO~- (~2A')，HBeO~- (~1∑~+)，HBeF~- (~2A')， BBeB~- (~2A_1)，H_2BO~-(~1A_1) and H_3BO~-(~2A') are calculated at the B3LYP/6-311 + + G(3df, 3pd) and G3 level. Besides, the potential energy curves of BeF(2~∑~+)/BeF~-(~1∑~+)，BF(~1∑~+)/BF~-(~2∏), BF (~3∏)/BF~-(~4∑~-) are constructed by CASSCF-MRCISD calculations. Stability of these molecules is discussed. The related results observed in measuring Be are well explained.

Key words: BERYLLIUM, BORON, ELECTRONIC STRUCTURE, POTENTIAL ENERGY, STABILITY