Global adiabatic potential energy surfaces (PESs) of the lowest three doublet states (1 A(2)A('), 2 (2)A('), and 1 (2)A(')) for the BrH2 system have been calculated using the multireference configuration interaction (MRCI) method including the Davidson's correction (Q) with the aug-cc-pVTZ basis set. Spin-orbit effects were considered on the basis of the Breit-Pauli Hamiltonian using the MRCI wave functions. The calculated adiabatic energies were fitted to the analytical functional form of many-body expansion. The barrier heights of the H+HBr-->H-2+Br abstraction and H+(HBr)-Br-'-->H-'+HBr exchange reactions on the ground-state PES were calculated to be 1.28 and 11.71 kcal mol(-1), respectively, both of which are slightly smaller than the values obtained in the previous work [G. C. Lynch, D. G. Truhlar, F. B. Brown, and J.-G. Zhao, J. Phys. Chem. 99, 207 (1995)]. The fits for the 1 (2)A('), 2 (2)A('), and 1 (2)A(') PESs were successful within an accuracy of 0.1 kcal mol(-1) in the important regions of PESs such as the transition states and van der Waals wells. Thermal rate constants for the abstraction and exchange reactions and their isotopic variants were calculated with the fitted 1 (2)A(') PES using the improved canonical variational transition-state theory with the least-action adiabatic ground-state approximation method. The calculated rate constants were found to agree better with experiment than those obtained by Lynch (C) 2003 American Institute of Physics.