Abstract: Moire method and Linear finite element are used in order to study the failure mechanism of pin-loaded hole in orthotropic laminates.All the stages of deformation are recorded by Moue,including linear elasticity,sudden cracking,steady crack propagation and unsteady crack propagatiom.Not-only the distributions of displacement and strain at the vicinity of the hole but also the tensile cracking progress are obtained.Before crack appears,results of Moire agree quite well with that of linear finite element;and after crack propagates,Moire method describes the nonlinear properties of the pin-loaded hole.The orthotropic laminates used is of (0°n/90°m)s,n:m=1:1.The frequency of both specimen and reference gratings is 1000 L/in.The strain concentration factor K_c at the hole boundary is a constant before crack appears,and no-longer keeps constant after cracking.Three stages exist in the extension of the crack;sudden cracking,steady extension and unsteady extension until failure.At the second stage,the crack jumps forword step by step along the horizontal fiber orientation.The strain field at the crack tip moves forword in the same direction.The dimensions and the distribution forms of the field keep unchanged.The existance of the crack has no effect on the dimension of the compressive zone.The failure of laminates is brittle and the steady extension stage is short.The maximum strair at the boundary of the hole linearly varies with the applied load before crack appearss and nonlinearly after crack extends.In the steady extension,the crack opening angle is a constant,and the crack opening displacement at the tip presents nonlinear propeties.