Abstract: The longitudinal tensile and compression test s were conducted on the pre-damaged three-dimensionalbraided composites. The varying rules of tensile and compressive properties and the failure mechanism of the materials were investigated. Four kinds of damage processes were discussed , single-edge cut on the width , single-edgecut on the thickness , double-edge cut on the width and edge cut on the thickness and width. Experimental resultsreveal that the cut edge on the width of specimen barely affects the longitudinal properties , except that the compressive modulus deduces by 20 %; while cut on the thickness makes a relatively great deduction on the properties.When the surface angle is 20°, stress-strain curves of tension and compression tend to linearity , and the failuremechanism has brittle f racture characteristics ; when the surface angle is 35°, the stress-strain curves of compressionexpress non-linearity to some extent .