In this paper,we consider the strategic interaction between the normal and sharp traders in a dynamic limit-order security market and its impact on the Chinese security market at different market volatility levels.We find that when the proportion of sharp traders is less than a threshold in an orderdriven market,the sharp traders who submit limit orders will get more rets than the normal traders.The participation of sharp traders in the market can increase the total social welfare of all the traders.In addition,we show that:(1) when the market volatility level is generally low,the short-term sharp traders benefit from larger volatility;(2) when the market volatility level is generally high,the insider/cheating sharp traders with high-frequent trading rather than the short-term sharp traders benefit from extreme high volatility;(3) when the market volatility level is moderate,the sharp traders can increase market liquidity.