A new method for the determination of the parameter in the pseudopotential of the simplified Heine-Abarenkov model is proposed. In the present method the values of the parameter γc in the pseudopotential and the correction coefficient H for the average value of electron-ion interaction energy are determined from the experimental data of the bulk modulus and the lattice constant of the crystal at 0 K and 0 kbar. The equations of state for eleven simple metals (Li, Na, K, Rb, Cs, Ca, Al, Mg, Zn, Si and Ge) are calculated by means of this model potential and the second order perturbation theory. The calculated pressure-volume relations at 293K are compared with the experimental data. The agreement for all metals is fairly good except Zn for which the discrepancy between the different experimental data is relatively large.