The effects of Mn microalloying on the microstructure and mechanical properties of new near-α Ti-Al-Mo-Zr-Fe-B alloy were studied by OM, EBSD, and TEM. Results indicate that the addition of 0.5wt% Mn can refine the casting microstructure of the alloy from 3.28 μm to 2.65 μm, which leads to the increase in ultimate tensile strength from 882 MPa to 966 MPa. However, the elongation decreases from 7.8% to 5.1%. After forging, the grain size of two alloys tends to be similar, and the microstructure is more equiaxed. Besides, the microstructure becomes more homogeneous after Mn microalloying. The ultimate tensile strength and elongation of Ti-Al-Mo-Zr-Fe-B alloy increase to 966 MPa and 16.4%, respectively, whereas the alloy containing 0.5wt% Mn element possesses higher ultimate tensile strength, reaching 1079 MPa. Meanwhile, the elongation reaches 15.8%. These results suggest that the increase in strength can be attributed to the solid solution strengthening effect of Mn element. Additionally, the Mn microalloying promotes the enrichment of Al element in alloy into the α phase, which is beneficial to improve the strength and plasticity of the alloy.