In order to improve the defect of incompleteness, three-dimensional I-shaped fabrics with basalt fiber filaments tows were woven on the semi-automatic loom by reasonable design. Three-dimensional I-shaped woven composites were prepared by the vacuum-assisted resin transfer molding process. The compressive behaviors of three-dimensional I-shaped woven composites with three different heights and thicknesses were studied. Through the evaluation of load–displacement curves and total energy absorption of the three-dimensional I-shaped woven composites, the results indicated when the thickness was fixed to 2 mm, the maximum compression load with height 20 mm raised 522.72 N as against that with height 60 mm and the maximum compression load with thickness 6 mm raised 2571.81 N as against that with thickness 2 mm. Consequently, the compression properties of three-dimensional I-shaped woven composites decreased with the increasing heights of the composites, while increased with the increasing thickness of the composites. Analyzing morphological characteristics of composites after fracture and load–displacement curves of composites, it was concluded that the compression failure modes had brittle fracture of the fiber bundle, cracking of the matrix, and a typical shear failure in the beam (A2). Despite the above-mentioned failure mechanisms, the three-dimensional I-shaped woven composite still had good integrity without delamination.