Abstract: The mechanical properties of three-dimensional and four-directional braided composites were investigated by macroscopic compressive experiments. The experimental results show that the mechanical properties and compressive failure mechanism of the composites change with the increase of the braided angles. When the braided angle is small, the material behaves as the brittle characteristics. But if the braided angle is larger than a critical angle, the stress-stain curve of the specimen approaches nonlinear, behaving mostly as the characteristics of plastic failure. The acoustic emission data can reveal the damage evolution during the compressive testing.