The non-equilibrium molecular dynamics simulation (NEMD) has been performed based on the embeded atom potential to obtain the pair correlation function and the viscosity of liquid Al.The pair correlation function by the simulation agrees well with Waseda's X\|ray diffraction measurement.The temperature dependence of viscosity meets the Arrhenius formula:η=Aexp(E/RT) and the activation energy E calculated is 15968.27J/mol.The expression between the viscosity, pair correlation function and the inter-atomic potential has been obtained by application of the simulated viscosity value and the activation energy to meet L-J potential.The two fitted curves of viscosity agree well with that obtained by the NEMD method,showing the fitting program we compiled is excellent and the fitting to the L-J potential is achieved.This present work provides a new method to explore inter-atomic potential.