In this paper, we consider the two-gap Ginzburg-Landau (G-L) free energy
functional including the interactions, and obtain a very simple and explicit
formula which presents the relation between the critical current density and
temperature. The result shows that the temperature dependence of critical
current density of a two-gap superconductor is of the form
* − T)1/2 at low temperatures and J
* − T)3/2 near the critical temperature. Our critical current density expression is in accord with the previous theoretical work and experimental data.