Based　on　the　discussion　of　characteristic　and　mechanism　of　the　stock　prices　volatility　in　Chinese　emerging　stock　markets,　this　research　designs　an　index　system　for　risk　forewarn,　and　builds　up　an　investment　decision　model　based　on　the　forewarn　of　the　market　risk　signal.　Then,　on　probing　into　the　structure　and　function　of　the　realization　of　the　model,　the　paper　presents　the　method　of　data　interface.