Two expressions presented in this paper may be employed to calculate the value of longitudinal focal displacement of the reflected beam from an absorbing medium for both s and p polarization. Our calculations show that Fp is positive (p-wave shifts alongthe reflected direction), and Fs is negative (s-wave shifts along the oppositive). Assuming that the extinction coefficient equals to zero, the two expressions can be simplified to the forms given by C. C. Chan and T. Tamir which fit only for the non-absorbing medium.