It is important to understand the damage and failure mechanism of unidirectional SiC/SiC composites during tensile process for mastering the mechanical behavior of SiC/SiC composites. In this paper, the tensile behavior of unidirectional SiC/SiC composite materials was investigated via a two-dimensional microscale finite element model. The random fracture process of fibers was simulated by strength judgment; The iterface debonding phenomenon was modeled using the cohesive zone model; A continuous medium damage model for the matrix was established through the uniform mass method and fracture energy release rate, specifically targeting the phenomenon of matrix cracks. The model  successfully simulated the microscale failure mechanism and macroscale mechanical behavior of unidirectional SiC/SiC composite materials in a tensile process. The three microscale damage mechanisms interact and eventually caused the final failure of the entire composite material. The results obtained in this paper might deepen the understanding on the tensile behavior of unidirectional SiC/SiC composite materials.