To investigate the fracture mechanical properties of dredged sand concrete，three-point bending fracture tests are carried out on the concrete specimens with different dredged sand replacement rates(0%，12.5%，25%，37.5%，50%).The whole fracture process of concrete is monitored with acoustic emission technology.The Weibull distribution damage model based on acoustic emission event is built，and the variation rules of model parameters are analyzed.The results show that with the increase of dredged sand content，the initial and unstable fracture toughnesses decrease firstly and then increase.The acoustic emission ringing count and energy reflect the three stages of fracture failure process of dredged sand concrete.With the increasing of dredged sand content，the accumulated acoustic emission count and energy increase.With the increasing of the dredged sand content，the brittle of concrete increases，the damage accumulation rate increases and the displacement corresponding to initial damage of the concrete decreases.