Abstract: Existing defects has an important influence in use of GFRP during preparation and use of GFRP. In order to achieve the mechanical properties of stretching damage, failure characteristics and acoustic emission(AE) response behavior of glass fiber composites with fiber pre-broken and weak bonding, stretching tests and real-time AE monitoring of glass fiber composites were conducted. Experimental results showed that the relationship between load and displacement of glass fiber composites was non-linear during the loading process. Damage model such as matrix cracking and fiber fracture and bending could be occurred in the process of damage and failure. The composition and content of signal frequency of AE is also different because of difference of preset defect.