We study color confinement properties of the multi-instanton system, which seems to carry an essence of the nonperturbative QCD vacuum. Here we assume that the multi-instanton system is characterized by the infrared suppression of instantons as $f\left(\rho \right)\sim {\rho }^{-5}$ for large size $\rho .$ We first investigate a monopole clustering appearing in the maximally Abelian (MA) gauge by considering the correspondence between instantons and monopoles. In order to clarify the infrared monopole properties, we make the “block-spin” transformation for monopole currents. The feature of monopole trajectories changes drastically with the instanton density. At a high instanton density, there appears one very long and highly complicated monopole loop covering the entire physical vacuum. Such a global network of long-monopole loops resembles the lattice QCD result in the MA gauge. Second, we observe that the $\mathrm{SU}\left(2\right)$ Wilson loop obeys an area law and the static quark potential is approximately proportional to the distance R between quark and antiquark in the multi-instanton system using the SU(2) lattice with a total volume of $V=(10\mathrm{}\mathrm{fm}{)}^4$ and a lattice spacing of $a=0.05\mathrm{}$ fm. We extract the string tension from the $5\times {10}^6$ measurements of Wilson loops. With an instanton density of $\mathrm{}(N/V)=(1/\mathrm{fm}{)}^4$ and an average instanton size of $\overline{\rho }=0.4\mathrm{}$ fm, the multi-instanton system provides a string tension of about 0.4 GeV/fm.

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