There is a possibility of high attack angle at an elevation of the main girder of a long-span bridge in the mountainous terrain or during the typhoon process. At the same time, with the increase of bridge main span, the additional attack angle of the main deck may be higher. Aiming at the flutter stability of the main girder at high attack angles, this paper studies flutter stability of a thin plate and a streamlined box girder section at different attack angles (0o, ±3o, ±5o, ±8o) by numerical simulation method. Two-dimensional fluid-structure interaction (FSI) method was developed that combined with , which is based on ANSYS FLUENT user-defined function (UDFs) and dynamic mesh technology. The results show that the critical flutter wind speeds of the thin plate section and the streamlined box girder section by numerical simulation method are in good agreement with those from wind tunnel tests, which verifies the accuracy of the two-dimensional FSI analysis method for bridge deck section. The flutter critical wind speed of the thin plate section decreases significantly with the increase of attack angle. The flutter critical wind speed of the streamlined box girder section decreases with the increase of attack angle in the range of positive attack angles, and increases firstly and then decreases with the increasing of absolute values of attack angles in the range of negative attack angles. When the attack angle is large enough, the thin plate section and the streamlined deck section all characterize bluff body, therefore the incoming flow passes around the leading edge of the section will separate and generates large vortices along the upper and lower edges of the section, which leads to the decrease of the critical flutter wind speeds of the bridge girder section.