Deformation behavior of carbon nano-tubes reinforced magnesium matrix composites was simulated by a simplified model based on the FEM（finite element method）to understand the strain and stress distribution in the matrix and reinforcement as well as effects of interface on mechanical properties of the composites

and stress transferring and fracture mechanism of carbon nao-tubes with the magnesium matrix alloy were expounded.The results reveal that the whole carbon nano-tube exhibits homogeneous stress distribution

however

the stress aggregation occurs in interface at axial direction to some extent.Remarkable stress aggregation can be observed in the contacted location of two-end face of matrix with carbon nao-tubes

where stress distribution exhibits flamboyance

decreasing from the center to the outer

while the stress distribution in the other location of the matrix alloy is very homogeneous.The fracture of the composites begins at the interface

and the fracture mechanism is characterized by interfacial debonding

which is accordant with the experimental ones.