Abstract: An eighth-order Runge-Kutta(R-K)recurrence formula is constructed for differential equations.The formula i8 used tu simulate formation and movement of polarons in a one-dimensional poly-phenylenevinylene(PPV)molecular chain.The PPV chain composed of N carbons is described by an extended tight binding model.For N=160.the equations are solved by eighth.order R.K method.Stable polaron configuration and moving picture are obtained.Under electric field E=1×10⁵V×cm^-1.a poiaron moved along PPV chain at a velocity of 0.263 5Å·fs^-1.It indicates that the eighth-order R-K formula is applicable to carrier movement in organic molecules.