The utility model provides a 3-DOF (degree-of-freedom) external store flutter simulation model for wind tunnel tests. The model comprises an external store, a rolling beam and a suspended beam hung on an aircraft aerofoil model. The rolling beam is arranged under the suspended beam. The rolling beam is connected with the suspended beam in a hinged way through a first articulated shaft. The first articulated shaft is horizontally arranged. The axial direction of the first articulated shaft is consistent with the length direction of the rolling beam. An elastic device is arranged under the rolling beam. The elastic device is connected with the rolling beam in a hinged way through a second articulated shaft. The second articulated shaft is perpendicular to the first articulated shaft. The external store is connected on the elastic device. The external store can perform pitching motion relative to the rolling beam along the vertical direction through the elastic device. The 3-DOF (degree-of-freedom) external store flutter simulation model for wind tunnel tests can achieve 3-DOF vibration mode decoupling and simulating. The external store flutter model design level is greatly improved. Furthermore, the flutter wind tunnel test result precision is enhanced.