A　model　of　structure　dynamic　neural　network,　which　simulates　the　learning　skills　such　as　human　beings　and　animals,　is　proposed　in　this　paper.　This　model　contains　two　main　steps:　1　the　structure　learning　phase　possesses　the　ability　of　online　generation　and　ensures　the　number　of　the　neural　nodes　of　the　neural　network　2　the　parameter　learning　phase　adjusts　the　interconnection　weights　of　neural　network　to　achieve　favourable　approximation　performance.　The　structure　learning　algorithm　consists　of　growing　and　pruning　methods,　and　then,　the　Lyapunov　stability　theory　is　used　to　analyse　the　stability　of　this　new　algorithm.　Finally,　this　new　dynamic　neural　network　is　used　to　track　the　non-linear　functions;　simulation　results　show　that　this　new　algorithm　can　achieve　favourable　performance.　Copyright　©　2010　Inderscience　Enterprises　Ltd.