The finite element method was used to simulate and analyze I-shaped beam which was made of the three-dimensional braided composite and suffered from bird impact. The models contained five braiding modes, two kinds of three-dimensional three-directional braiding and three kinds of three-dimensional six-directional braiding. Three kinds of thickness (10 mm, 15 mm and 20 mm), and all of these models were impacted by three different velocities (80 m/s, 150 m/s and 200 m/s) respectively. The bird has different mechanical properties in different velocities; therefore, different finite element models were used. Also, the stiffness of the braided composites degraded while damaged was absolutely considered. The numerical results indicated that, the capability of anti-bird impact was best when the beam was made of three-dimensional six-directional braided composites with sizes proportion of braiding yarn 1:1:1 for the four-directional, five-directional and six-directional. After analysis, the most reasonable braiding mode and structure dimension was obtained, in which condition the I-shaped beam was strong enough to resist bird impact and less weight.