The model of cross-flow tube bundle channel look like column body of surrounding flow in water conservancy project or tubes of surrounding flow in heat exchange.The paper introduced periodic boundary condition to simplify model ,and investigated flow field and temperature field in different values of Re by numerical simulation. It is discovered that with the increase of Re number,flow changes from stable to the appearance of bigger vortex，then becomes smaller and then grow bigger,which is a circulation process. The reason is that with the increase of Re number，the inertial force, viscous force and micro vortex of continuous generation combine action. The process of heat transfer are closely related to flow. In addition, the change trend of the speed at monitoring point with time is investigated, it is found that the flow exhibits nonlinear properties.With the increase of Re number, the numerical solution from steady state to periodic oscillation and finally develop into a state of chaos.