Abstract: This psper proposes a theoretical method to analyza the buckling and postbuckling bachavior of multi-laverel fiber reinforeed composite cvlindical shells under uniform axial or hedrostatic compression. The influences of shear nonlincarity of the composite material and the initial imperfection of the shell geometry are taken into account. For the competation of the critical form potential energy method is used. Numerical results are given for boron epoxy temposite cylindrical shells with various fiber orientation and diffreent layer numbers. Results show that the shear nonlinearity of the composite materials and the initial imperfections of the shells are both important for the composite and postbackling behavior of the composite cylineleical shells.