\documentclass{minimal}
\usepackage{pstricks}
\usepackage{pst-tree,pst-node}
\usepackage{lscape}
\SpecialCoor
\makeatletter
\def\MyNodeA{\@ifnextchar[{\MyNodeA@i}{\MyNodeA@i[]}}
\def\MyNodeA@i[#1]#2{\Tr[#1]{\psframebox{#2}}}
\def\MyNodeB{\@ifnextchar[{\MyNodeB@i}{\MyNodeB@i[]}}
\def\MyNodeB@i[#1]#2{\TR[#1]{\psframebox{#2}}}
\def\MyNodeC{\@ifnextchar[{\MyNodeC@i}{\MyNodeC@i[]}}
\def\MyNodeC@i[#1]#2#3{\Tr[#1]{\rnode[b]{#2}{\psframebox{#3}}}}
\makeatother

\parindent=0pt
\pagestyle{empty}
\begin{document}

\begin{landscape}
\pstree[levelsep=7,arrows={-*},arrowscale=2,nodesepB=0.1]{

  \MyNodeA[ref=b]{Niveau 1 : Accueil}}{%

    \pstree[treesep=0.2,levelsep=5]%
      {\MyNodeC[ref=t]{Computation}{Niveau 2.1 : Master 1}}{%
        \def\pspred{Computation}%
        \MyNodeB[href=0.6]{Formation}
        \psset{levelsep=0.8,labelsep=0.05,tpos=0.8}%
        \skiplevels{1}
            \MyNodeB[href=-0.4]{%
            \Rnode[href=-0.4]{Linear}{Scolarit\'e}}
        \endskiplevels
        \skiplevels{2}
            \MyNodeB[href=-0.6]{examens}
        \endskiplevels
        \skiplevels{3}
            \MyNodeB[href=-0.6]{M\'emoires}
        \endskiplevels
    }%

    \pstree[treesep=0.3,levelsep=3]%
      {\MyNodeC[ref=t]{Computation}{Niveau 2.2 : Master 2 Pro (APEI)}}{%
        \def\pspred{Computation}%
        \MyNodeB[href=0.6]{Formation}
        \psset{levelsep=0.8,labelsep=0.05,tpos=0.8}%
        \skiplevels{1}
            \MyNodeB[href=-0.4]{%
            \Rnode[href=-0.4]{Linear}{Scolarit\'e}}
        \endskiplevels
        \skiplevels{2}
            \MyNodeB[href=-0.6]{examens}
        \endskiplevels
        \skiplevels{3}
            \MyNodeB[href=-0.6]{M\'emoires}
        \endskiplevels
    }%


    \pstree[treesep=0.3,levelsep=3]%
      {\MyNodeC[ref=t]{Computation}{Niveau 2.3 : Master 2 Pro (APLN)}}{%
        \def\pspred{Computation}%
        \MyNodeB[href=0.6]{Formation}
        \psset{levelsep=0.8,labelsep=0.05,tpos=0.8}%
        \skiplevels{1}
            \MyNodeB[href=-0.4]{%
            \Rnode[href=-0.4]{Linear}{Scolarit\'e}}
        \endskiplevels
        \skiplevels{2}
            \MyNodeB[href=-0.6]{examens}
        \endskiplevels
        \skiplevels{3}
            \MyNodeB[href=-0.6]{M\'emoires}
        \endskiplevels
    }%

    \pstree[treesep=0.3,levelsep=5]%
      {\MyNodeC[ref=t]{Computation}{Niveau 2.4 : Master 2 Recherche}}{%
        \def\pspred{Computation}%
        \MyNodeB[href=0.6]{Formation}
        \psset{levelsep=0.8,labelsep=0.05,tpos=0.8}%
        \skiplevels{1}
            \MyNodeB[href=-0.4]{%
            \Rnode[href=-0.4]{Linear}{Scolarit\'e}}
        \endskiplevels
        \skiplevels{2}
            \MyNodeB[href=-0.6]{examens}
        \endskiplevels
        \skiplevels{3}
            \MyNodeB[href=-0.6]{M\'emoires}
        \endskiplevels
    }%

}
\end{landscape}

\end{document}