In this paper, we study the obstacle problem of some convex operators, which is related to normalized p-Laplacian Δps\documentclass[12pt]{minimal}
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\begin{document}$$\Delta _p^s$$\end{document}. We prove that the graph of the regular free boundary is C1,α\documentclass[12pt]{minimal}
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\begin{document}$$C^{1,\alpha }$$\end{document} and the solution is C1,s\documentclass[12pt]{minimal}
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\begin{document}$$C^{1,s}$$\end{document} near these points. Moreover, we show that the set of regular free boundary points is relatively open.