A novel approach to averaged intermolecular potential field (AIPF) of methane from viscosity was developed. Using symmetric molecular interaction approximation and Maxwell-Boltzmann distribution function of velocity, equations relating the AIPF and viscosity have been derived. Applying the equations to methane, good agreements were found between high quality viscosity data and the equations via fitting method. Then a formula for methane's AIPF as a function of temperature and density was determined. Obtained results not only give a new method to estimate the AIPF for fluidic system, but also may form a novel base to study the viscosity of other alkane mixtures. (C) 2017 Elsevier B.V. All rights reserved.