The possible geometrical configuration of B2H6 molecule of D3d,D3h，D2d and planar or stereo D2h have long been argued about.In this work different methods of B3P86,BP86,B3LYP,BLYP,UHF,HF and LSDA in Gaussian 98 program have been used to optimize the structure of B2H 6.Our result shwos that the ground state geometrical configuration for B2H6 molecules is stereo D2h,i.e.,the three-center two bridge hydrogen structure,in wh ich two boron and four hydrogen atoms lie in a plane while the other two bridge hydrogen atoms lie in a plane perpendicular to it.This three-center two bridge hydrogen structure is more stable than two-center two-electron bond structure.