A plate with uniform boundary layer suction is developed，on which the boundary layer can be controlled. The boundary layer velocity distribution on this plate is studied in various main flow velocities and suction coefficients. The experimental results are consistent with the calculation's，and the experimental results of the high speed train models on this plate are also consistent with the foreign results of the similar models on moving ground. The effect of the boundary layer can be eliminated effectively by using uniform suction plate，and thereby the air forces of models can be measured more exactly.