The quantum chemical investigations of some representative bis-adducts of C_60, C_60O_2, C_60(NH)_2, C_60(CH_2NHCH_2)_2 and C_60(SO_4)_2 have been carried out at the AM1 and PM3 semi-empirical molecular orbital levels. The relative energies of various isomers of these C_60 bis-adducts have been calculated. For C_60O_2 and C_60(NH)_2 with the sterically non-demanding addends, cis-1 isomer resulted from 1,2-additions to adjacent 6/6 ring fusion is the lowest energy structure; for C_60(CH_2NHCH_2)_2 and C_60(SO_4)_2 with sterically demanding addends, the most energetically preferred structure is e isomer. This is consistent with and enhances the general rule for regio-selectivity of fullerene C_60 established by Hirsch, though Hirschs rule is summarized on the basis of methanofullerenes. The thermodynamic analysis is not significant to explain the experimentally observed regiochemistry for C_60 bis-adducts, and the kinetic reasons or mechanisms may dominant in determining the regioselectivity of fullerene bis-adducts. Further addition patterns for multiple addition were also discussed. The quantum chemical investigations of some representative bis-adducts of C_60, C_60O_2, C_60 (NH) _2, C_60 (CH_2NHCH_2) _2 and C_60 (SO_4) _2 have been carried out at the AM1 and PM3 semi-empirical molecular orbital levels. The relative energies of various isomers of these C_60 bis-adducts have been calculated. For C_60O_2 and C_60 (NH) _2 with the sterically non-demanding addends, cis-1 isomer derived from 1,2-additions to adjacent 6/6 ring fusion is the lowest energy structure; for C_60 (CH_2NHCH_2) _2 and C_60 (SO_4) _2 with sterically demanding addends, the most energetically preferred structure is e isomer. This is consistent with and enhances the general rule for regio-selectivity of fullerene C_60 established by Hirsch, though Hirschs rule is summarized on the basis of methanofullerenes. The thermodynamic analysis is not significant to explain the experimentally observed regiochemistry for C_60 bis-adducts, and the kinetic reasons or mechanisms may dominant in determining the r egioselectivity of fullerene bis-adducts. Further addition patterns for multiple addition were also discussed.