The permeation of polymer chains through a small hole is simulated using dynamic Monte Carlo method. The dependence of the permeation velocity v on concentration C of polymer chain, chain length n and hole size s is investigated. The velocity v increases non-linearly with C, differing from linear dependence of hard sphere system, indicating that inter-chain interaction plays an important role in the permeation process. At the same concentration, the velocity decreases with the chain length n via a relation v = a + bn(-phi) where the exponent phi increases linearly with C. Such a behavior is different from a single chain system. The possible physical reason is addressed. The velocity is proportional to hole size when the chain size is smaller than the hole size, but it decreases obviously if the chain size is much larger than the hole size. (c) 2005 Elsevier Ltd. All rights reserved.