Abstract: TiB₂ /Al composites with TiB₂ contents of 3wt%, 5wt% and 8wt% were prepared by in-situ technology. The generating state of the in-situ TiB₂ phase from the microscopic mechanism was analyzed by metallographic structure analysis and scanning electron microscope analysis. The results show that, the size of TiB₂ phase is about 1-2 μ m, which is uniformly distributed in the matrix. At the same time, there are a small amount of Al₃Ti phase surplus in the metallographic structure.With the increase of TiB₂ content, the tensile strength of the composites increases gradually. When the TiB₂ content is 5wt%,the tensile strength of the composites reaches 110 MPa, and the elongation decreases gradually, down from 22.5% in pure aluminum to 15.5% at 8wt% TiB₂ content.