针对β锻制备的航空用TC21钛合金变截面模锻件的组织和力学性能不均匀性，采用Deform软件模拟、OM、SEM、XRD、EBSD、拉伸和示波冲击，对不同等效应变处的显微组织和力学性能进行表征，对比分析了影响拉伸和冲击及其各向异性的主要因素。结果表明，模锻件整体形状复杂，等效应变集中于0.75~1.20范围，应变高处流线组织明显，亚结构增多，窄截面导致冷速较快，使得初生α相含量减少以及次生α相细化，共同导致了强度升高。分析了高应变处在热变形和热处理过程中各相组成的织构演化，最终为残余β相的<110>//LD的强织构及转变α相的{0002} 2种较弱织构，从α相滑移系和β相密排面分析了强织构导致的强度各向异性。示波曲线表明冲击功主要消耗于萌生能，结合原始β晶粒排布讨论了不同取向冲击和拉伸断口的断裂模式差异，最后提出拉伸断裂模型，解释了高应变1.20处具有良好强塑性匹配的原因。

TC21 titanium alloy has been successfully used in the structural die forgings of aviation owing to its excellent damage tolerance. However, because of the difference in the equivalent strains of die forgings, the microstructure and properties of variable cross-sections are considerably different, affecting the service life of the structural parts. Therefore, the microstructure and mechanical properties of β-forged TC21 titanium alloy die forgings with variable cross-sections were characterized using Deform software simulation, OM, SEM, XRD, EBSD, and tensile and impact tests, and the primary factors affecting the tensile and impact properties as well as their anisotropy were comprehensively analyzed. The results showed that the overall shape of the die forgings was complex and the effective strain was concentrated in the range of 0.75-1.20. The evidence of the flow was obvious at high strain, the substructure increased, and the narrow cross-section led to a faster cooling rate. This resulted in the decrease of α_p content and refinement of α_s, which together led to the increase in strength. The evolution of various texture components under high strain during thermal deformation and heat treatment was analyzed, and finally the strong texture of residual β phase <110>//LD and {0002} weak texture of transformed α phase were formed. The strength anisotropy caused by the strong texture was analyzed from α phase slip system and β phase densely packed plane. The impact load-displacement curves showed that the impact energy was mainly consumed via the initiation energy. Combining with the prior β grain arrangement, the fracture modes of impact and tensile fracture in different orientations were discussed. Finally, a tensile fracture model was proposed, which explained the reason that there was a good strength and plastic matching at a high strain of 1.20. This work provides material research support for optimizing the uniformity design of TC21 alloy variable cross-section die forgings.