Abstract: Based on a relationship among potential equivalent temperature,equivalent temperature and pressure,a linear link is shown to exist between potential equi -valent temperature and equivalent temperature at a given pressure while a nonlinear link is found between potential equivalent temperature and pressure at a given equivalent temperature.A new scheme for calculating the fiducial pressure is then proposed According to it,the T_eη which corresponds to the θ_eη can be interpolated linearly during the first adjustment and then the P_η corresponding to θ_eη can be calculated by another form of the same relation:P_η=EXP(LN(1000)-(C_P/R_d)*LN(θ_eη/T_eη)).When areal question is considered,it would be best to take spatial mean during the second adjustment,for some higher or lower θ_e without corresponding to P_r may appear in using the temporal mean.The third adjustment,similar to the first one,must be added if there is unstable stratification after the first two adjustments.Compared with the previous version,of the scheme it exhibits significant advantages in determining the fiducial pressure objectively and calculating the wet available energy accurately.