On the standpoint of the urbaryon model with approximate U(6) symmetry, several relations among the differential cross sections relevant to η and η′ mesons are obtained. It is shown that the overlapping integral between the spatial wave functions of the singlet and the 35-plet mesons plays an important role. Obtained relations well agree with experiments for the case of the quadratic mass formula, but not for the linear mass formula. Decays of η or η′ meson and heavy meson decays to η or η′ meson are also discussed.