A finite element analysis of crack propagation in an HDPE/CaCo3 composite was carried out using a combination of the extended finite element method (XFEM) and the cohesive zone method (CZM). A unit cell of an entire composite consisting of one particle was chosen as the study zone. The interphase was assumed as a cohesive surface between the matrix and the particle. Variable parameters were the interface adhesion, position of initial crack, volume fraction, and size of the particle. The results showed that, the energy release rate increases when increasing the particle size. Increasing the volume fraction from 5 to 10% has positive effects in decreasing the strain energy release rate; however, the effects of 10 and 15% of volume fraction on the energy release rate are almost the same. Increasing the values of interfacial adhesion strength increases the strength of composite.