Abstract: Accurately obtaining the turbulence level at the outlet of the combustion chamber of the gas turbine is crucial for controlling the heat load of the high-pressure turbine and reducing thermal corrosion. By adding turbulence grids at the inlet of the experimental section of the cascade wind tunnel, turbulence level was simulated to range from 5% to 13%. The unsteady velocity in the wind tunnel and the unsteady pressure on the lower wall of the tunnel were obtained using a hot wire anemometer and four microphones respectively. The correlation function was constructed using linear stochastic estimation, and the unsteady velocity and turbulence were estimated using unsteady wall-pressure at conventional temperature. The results show that in the cascade wind tunnel, the correlation between unsteady pressure and unsteady velocity is lower than that of special structures such as cavities and steps; Compared to orifice grids, circular grids can induce higher turbulence levels, but lead to a further decrease in correlation; By modifying the expression of correlation function, the estimated error can be controlled within 5% under low correlation cases. The existence of grids disrupts the large-scale vortex structure in the cascade channel, which is the main reason for the decrease in correlation. By modifying the expression of correlation function, effective prediction of high turbulence conditions can be achieved at conventional temperature, providing a new method for related experiments in medium and high temperature environments.