Nucleon-antinucleon annihilation process at low energies has been explained by the quark rearrangement model with parameters gα, where gα describes the strength for a quark-antiquark pair to combine into α meson (π, η, ρ, ω). This parameter has strong dependence on the kind of the meson and is in the order of the meson mass. It is shown that these properties originate from the overlapping of quark wave functions of hadrons. The relation to the potential model for NN interaction is also discussed.