Abstract: Since the leakage rate of pressure leak will vary with its inlet pressure and outlet pressure,a correction should always be made in the calibration value for the operating pressure different with its calibration pressure.In this paper,two metal flattening pressure leaks were calibrated with different pressures,the results are given.The equations to calculate leakage rate of pressure leak are presented in accordance with the theory of conductance of pipe.Then,the comparison of results is presented.