Stock' s daily price limits are one of the most used approaches to restrain the excessive volatility of stock market.But the debate that whether cool effect or magnet effect is the predominant effect becomes the fo- cus of the policy for a long time since it has been put forward.An econometric model is constructed to test the existence of magnet effect in the paper.With China stock market' s intraday trading data,some empirical re- search is done and shown that there exists strong upward magnet ...