The range of Mach number of 1.3 to 1.5 is defined as low-supersonic flow in wind tunnel testing, which is necessary range for major fighters, aerospace vehicles, and missiles to reach the cruise state. It is also the most difficult test range for conventional ground simulation equipment due to sound barrier and uniformity of artificial air flows. In order to expand the test range of 2.4m transonic wind tunnel, researches on low supersonic flow filed calibration was carried out, and the geometrical parameters of perforated walls in test section were determined. Measured results of flow uniformity are compared with advanced wind tunnels using cross-shaped rake and cone-cylinder model. The results show that uniformed low supersonic flow in model testing area was obtained using newly developed nozzle together with perforated walls in 2.4m transonic wind tunnel, which effectively improve the simulation capability of the facility. Together with the capacity of 2m supersonic wind tunnel, seamless link of test data has been achieved in high speed regime, which has formed an integrated test platform for sub-, trans-, and supersonic speeds on the order of 2 meters.