Dynamics of the four-centered elimination reaction CH2OH+ --> CHO+ + H-2 has been investigated over the internal energy range 4.6 - 5.9 eV using the classical trajectory method. A realistic semiempirical potential reported previously [J. Chem. Phys. (in press, 1996)] has been used for the calculation; It has been found that the disposal of the nonfixed excess energy at the transition state and of the reverse critical energy can be considered independently as manifest in the sum rule analysis, The former is determined statistically while the latter dynamically. Based on the above idea, a method to determine the kinetic energy release distribution originating only from the reverse critical energy has been developed.