A modified shear-lag model accounting for the effect of the tensile stiffness of the ma-trix is proposed for solving the stress redistribution due to the failure of fibers and matrix in unidirec-tionally fibre-reinforced composites.The advantages of this model are simple,reasonable and accurateby comparison with the other similar modified shear-lag models.It can be further extended to study thestress redistribution with interracial damage between fibres and matrix.This paper quantitatively dis-cusses the influence of the tensile stiffness ratio of matrix to fibre and.of the fibre volume fraction onthe stress concentration in the fibres and matrix adjacent to cut fibres and matrix,and suggests that theinfluence of the matrix stiffness on the stress concentration can be neglected when the matrix stiffnessis low,such as polymer matrix composites,and the fibre volume fraction is high.For other cases suchas ceramic and metal matrix composites,the tensile load of the matrix cannot be neglected in the shear-lag analysis. A modified shear-lag model accounting for the effect of the tensile stiffness of the ma-trix is ​​proposed for solving the stress redistribution due to the failure of fibers and matrix in unidirec-tion fiber-reinforced composites. The advantages of this model are simple , reasonable and accurateby comparison with the other similar modified shear-lag models. It can be further extended to study thestress redistribution with interracial damage between fibers and matrix. This paper quantitatively dis-cusses the influence of the tensile stiffness ratio of matrix to fiber and . of the fiber volume fraction on the stress concentration in the fibers and matrix adjacent to cut fibers and matrix, and suggests that the impact of the matrix stiffness on the stress concentration can be neglected when the matrix stiffness low, such as polymer matrix composites, and the fiber volume fraction is high. For other cases suchas ceramic and metal matrix composites, the tensile load of the matrix can not be neglect ed in the shear-lag analysis.