The invention relates to a protection device for a pitching dynamic derivative balance. The protection device is composed of a connecting cylinder, two groups of supporting connecting rod mechanisms,two groups of linear motion mechanisms and two groups of connecting members. The two groups of linear motion mechanisms are symmetrically installed at the two sides of a motor fulcrum bar; and motionunits of the two groups of linear motion mechanisms are connected with two sides of one end of the connecting cylinder by the connecting members. The connecting cylinder sleeves a pitching dynamic derivative fulcrum bar; and the two sides of the other end of the connecting cylinder are fixedly connected with the pitching dynamic derivative fulcrum bar by the supporting connecting rod mechanisms. When a wind tunnel is opened or closed, the linear motion mechanisms drive the supporting connecting rod mechanisms to be lifted so as to support the inner cavity of the tail of a model; and thus the tail of the model is integrated with the pitching dynamic derivative fulcrum bar. According to the invention, the balance can be protected during the wind tunnel testing process. The protection deviceshas little impact on the flow field of the tail of the model, so that the high precision of the dynamic derivative testing is ensured.