The second order information in laboratory and in stock market is homogeneous. This particle designs a laboratory stock market with continuous bids to analyze the effect of different price limits in stock market. Result shows that the three categories of price limits debases volatility of stock price and the absolute value of fluidity in some degree; result of volatilitybased fluidity shows that price limits represent advance to fluidity when the effect of volatility is filtrating. By comparison, the best fluidity is obtained with the price limits of 20% extent while the volatility within and between the periods are debased obviously.