The model of Pouget is extended to investigate the impact of order transparency on the efficiency of order-driven markets where there are full of adaptive learning ( limited rational) investors． The results show that both the efficiency of information revealing and welfare allocation will deviate from rational equilibrium when in-vestors can observe the order details of the others in the regime of transparency． The reason is that the informed traders take advantage of their private information and submit non-equilibrium orders which are more beneficial to him． The uninformed traders also abandon the equilibrium strategy and submit more conservative orders to a-void adverse selection risk． Both of the traders’choice substantially reduce the market efficiency．