  We investigate the Hubbard chains network model defined on corner-sharing
tetrahedra (the pyrochlore lattice) which is a possible microscopic model for
the heavy fermion state of LiV_2O_4. Based upon this model, we can explain
transport, magnetic, and thermodynamic properties of LiV_2O_4. We calculate the
spin susceptibility, and the specific heat coefficient, exploiting the Bethe
ansatz exact solution of the 1D Hubbard model and bosonization method. The
results are quite consistent with experimental observations. We obtain the
large specific heat coefficient $\gamma\sim 222 {\rm mJ/mol K^2}$.
