The work aims to select the cavity structure scheme with the optimal performances from the five different cavities of flotation dryer with coated web drying. Five cavities of flotation dryer were modeled by 3D software, and the boundary conditions of five kinds of models were set with Fluent module of Ansys to simulate the working conditions of them. By means of the auxiliary planes and auxiliary lines, the hot air trajectory map inside the cavity and the wind speed contour map at different positions of the dryer when five dryers were working were obtained. By comparing the simulation results, flotation dryer with balanced wind diversion is better than other dryer structures.