It is not trial to develop a full-dimensional accurate PES for the OH + CH3OH reaction system. One reason is that the title system has 8 atom and 28 degrees of freedom (DOFs), and thus the sampling configuration space is huge, particularly, there exists long-range dipole-dipole interaction in the entrance channel. Another difficulty is the single reference method, UCCSD(T)-F12a, may result in some discontinuity along some dimensions, as the title system is of multi-reference in nature. Although carefully selected Hartee-Fock (HF) orbitals can delete the discontinuity, as proposed by us for the OH + HO2 system, 61 a single-point energy calculation at the level of UCCSD(T)-F12a/AVTZ still takes 30 ~ 70 minutes with 8 cores of a computational node with Intel Xeon CPU E5-2682 v4 @ 2.50GHz. It is expensive to determine the energies of 10 5 ~10 6 points directly at the UCCSD(T)-F12a/AVTZ level.