Mass attenuation coefficient(μ_m) for polyethylene glycol(PEG) of different molecular weights was determined by using NaI(Tl) scintillator and Win Xcom mixture rule at gamma energies of 59.5, 302.9, 356.0, 661.7, 1173.2 and 1332.5 keV. The total atomic, molecular and electronic cross sections, half-value layer, effective atomic and electron numbers, mass energy-absorption coefficients and kerma relative to air are calculated. The energy and compositional dependence of μ_m values, and the related radiation absorption parameters, are evaluated and discussed. The experimental results agree well with the theoretical ones, within an uncertainty of 1% in the effective atomic number for all PEG samples at the designated energies. Mass attenuation coefficient (μ_m) for polyethylene glycol (PEG) of different molecular weights was determined by using NaI (Tl) scintillator and Win Xcom mixture rule at gamma energies of 59.5, 302.9, 356.0, 661.7, 1173.2 and 1332.5 keV. The total atomic , molecular and electronic cross sections, half-value layers, effective atomic and electron numbers, mass energy-absorption coefficients and kerma relative to air are calculated. The energy and compositional dependence of μ_m values, and the related radiation absorption parameters, are evaluated and discussed. The experimental results agree well with the theoretical ones, within an uncertainty of 1% in the effective atomic number for all PEG samples at the designated energies.