  In this article, we calculate the strong coupling constant $g_{\Delta N\pi}$
and study the strong decay $\Delta^{++} \to p\pi$ with the light-cone QCD sum
rules. The numerical value of the strong coupling constant $g_{\Delta N\pi}$ is
consistent with the experimental data. The small discrepancy maybe due to
failure to take into account the perturbative $\mathcal {O}(\alpha_s)$
corrections.
