The perforated walls of transonic wind tunnels with different parameters have a considerable influence on the flow field quality of the test section, therefore, the characterization of the perforated wall parameters is extremely essential for the design of the test section of transonic wind tunnels. The relationship between the characteristic parameters near the perforated wall of three-dimensional and two-dimensional perforated wall models was studied using the single straight perforated hole of the FL-3 wind tunnel. The mass and velocity distributions of the two-dimensional and three-dimensional perforated wall show obvious linear characteristics under different pressure difference coefficients. It is proposed that the two-dimensional perforated wall can be equivalent to the flow characteristic parameters of the three-dimensional perforated wall by the corresponding coefficient transformation under the same incoming flow Mach number when the wall pressure difference coefficient and the boundary layer displacement thickness are satisfied. A two-dimensional calculation model of the transonic wind tunnel was established, and the effects of perforated wall parameters and free stream Mach number on the flow field and flow characteristic parameters near the wall in the test section were analyzed by numerical method. When l / d = 1, the increase in perforated wall size makes the wall pressure difference coefficient increase, otherwise, the relative area of flow in the perforated wall decreases. As d = 2 mm, the flow field was proposed. When l / d > 2, ΔC_p tends to be stable. When l / d = 3, m' and S / d are the maximum values, in the Ma = 0.8 ~ 0.9 range, m' is positively correlated with the incoming Mach number, but ΔC_p changes little. The pressure difference coefficient and velocity component obtained under different perforated wall parameters have certain guiding significance for understanding the perforated wall flow and adjusting the perforated wall of the test section.