Based on three dimensional continuum damage mechanics,an improved progressive damage analysis method was proposed for bi-modulus fiber-reinforced polymer（ BFRP） composites laminated structure. Firstly,according to the bi-linear model of bi-modulus materials and constitutive theory of orthotropic material,the stress-strain relation for BFRP composites lamina was described. Secondly,in-situ strength of lamina was calculated using Dvorak model. Plus,damage initiation and its evolution inside laminates were described by three-dimensional Hashin strength criterion and the exponential damage evolution criterion,and the cohesive element was used to describe the interlaminar mechanical behavior. Then,the progressive damage analysis code for BFRP composites laminated structure was realized through ABAQUS material subroutine UMAT. The new method was verified by comparing to the experimental results in literatures. Finally,this method is used to examine the load limit of a BFRP arm structure which is a part of space station and obtain the prediction results.