The validity and merits of the monetary policy is reflected in the level of the attainment of its ultimate goal. We build up a decision-making model of central bank and deduce the optimal money supply reaction function of considering and ignoring asset price. In order to clarify the relationship between the optimal monetary policy and asset price volatility, we simulate the macroeconomic performance of optimal reaction function of considering and ignoring asset price in a wide range of monetary policy objective. We conclude that monetary policy should respond to volatility of asset price directly.