The X-ray spectra of SS 433 were measured with ASCA at a precession phase 0.48 when the Doppler-shifted iron lines from both the receding and approaching jets were clearly separated. The X-ray emission lines of SS 433 were analyzed on the basis of a numerical model of the radiatively cooling jets. The measured intensities of the iron-emission lines were compared with the results from numerical calculations in order to constrain the physical parameters of the jets, such as the temperature, mass outflow rate, density, and length. We also studied the emission lines from elements with smaller atomic number, and found that these lines were heavily absorbed only in the receding jet. This implies the existence of absorbing gas in a precessing plane perpendicular to the jets.