Abstract: Using the B3LYP(Becke-3-parameter-Lee-Yang-Parr) method of density functional theory(DFT), the geometries and electronic structures of boron-doped carbon clusters of the type B2Cn+(n=1～9) have been optimized at 6-311G* basis set level. Frequency calculations at the same level of theory were performed to characterize the nature of the optimized structures. The calculation results show that most of the ground state structures for B2Cn+(n=1～9) clusters are planer except that for B2C2+ and B2C3+ are linear structure with D∞h symmetry and three-dimensional monocycle with Cs symmetry for B2C7+. The preference order for the bonding in the ground state of B2Cn+(n=1～9) clusters is C—C ＞ B—C ＞ B—B. In addition, the total energy(ET), zero point energy(EZ), molar heat capacity(Cp), standard entropy(S0) and atomization energy(ΔEn+) of B2Cn+(n=1～9) clusters are also obtained. The ET, EZ, Cp and S0 values tend to increase with increasing n, in which the increasing zero point energy(EZ) has an approximately constant gradient. The vertical electron affinities of the most stable B2Cn+(n=1～9) clusters indicate that B2Cn+ with odd n is more stable than that with even n.