  Transport surrounding is full of all kinds of fields, like particle
potential, external potential. Under these conditions, how elements work and
how position and momentum redistribute in the diffusion? For enriching the Fick
law in ordinary, nonequilibrium statistics physics need to be used to
disintegrate the complex process. This study attempts to discuss the particle
transport in the one-dimensional channel under external potential fields. Two
type of potentials, potential well and barrier do not change the potential in
total, are built during the diffusion process. There are quite distinct
phenomena because of different one-dimensional periodic potentials. We
meticulously explore reasons about why external potential field impacts
transport by the subsection and statistics method. Besides, one of the
evidences of Maxwell velocity distribution is confirmed in assumption of local
equilibrium. In addition, we have also investigated the influence of
temperature and concentration to the collective diffusion coefficient, by a
variety of external force, attaching thermodynamics analyze to these opposite
phenomena. So simply is this model that the most valuable point may be an idea,
which relating flux to sectional statistics of position and momentum could be
referenced in similar transport problems.
