Three⁃dimensional orthogonal composites were fabricated by a modified method and consolidated through the resin transfer molding(RTM) processing. The microstructure characteristic,interlaminar shearing properties and breakage configurations of three⁃dimensional orthogonal composites with different z⁃binder fractions were comparatively studied. The results indicate that yarns show excellent straightness based on the modified method. The z⁃binder fractions of 1%~5% are usually sufficient to greatly enhance the interlaminar strength and modulus. With the consolidation pressure increasing,the interlaminar strength is improved. However the growth rate of interlaminar shearing strength and modulus are decreased due to the distortion of yarns. Additionally,the predominant failure modes of composites under loading are identified to be fiber breakage,fiber pulling out and the separation be⁃tween z⁃binder and resin. Furthermore,the pore size between z⁃binders and matrix is decreased with increasing the z⁃binder size to prevent delamination.%采用置换法增强体成形工艺和树脂传递模塑（ RTM）固化工艺制备炭纤维三维正交复合材料。对比研究了不同z向纱体积含量的三维正交复合材料的细观结构、层间剪切性能和破坏形貌。结果表明，基于置换法成形工艺制备的三维正交预制体其3个方向的纱线具有优异的伸直性；z向纱的体积含量在1％～5％时，对材料的层间剪切强度及模量的增强作用明显；同时，随着固化成型压力的增加，材料的层间剪切强度呈上升趋势，但当压力增大到一定程度，纤维屈曲现象明显，从而降低层间剪切强度的增加幅度；在层间剪切载荷的作用下，材料的主要破坏模式包括纤维的断裂、抽拔以及z向纱与树脂的脱粘，但相应增加z向纱的细度，使z向纱与基体之间的孔隙尺寸减小，可防止材料分层现象的产生。
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