The dynamics and configurational-dependent properties of polymethylene (PM) chains are studied using the modified bond-fluctuation model and the rotational-isomeric state model. In this article, the tetrahedral lattice model is adopted because it gives a reasonable approximation to the carbon-carbon backbones of PM chain. In our bond-fluctuation model, a Kuhnian bond includes four carbon-carbon bonds. Our statistical mechanics properties of chains are in good agreement with the Flory theory. The relaxation times tau rise with the chain length N by a power law of the form tau (N) - N-2 in the absence of excluded volume and tau (N) - N-2.17 in the presence of excluded volume, and the diffusion coefficients D behave as D - 1/N both in the absence and presence of excluded volume. Our modified bond-fluctuation model can also be used to investigate the glass transition of polymer chains. (C) 1997 American Institute of Physics.