Composite structures in service are usually subject to complex loading conditions that can induce a stress field with two or even three dynamic principal stresses. The experimental analysis of composite structures could approximate the real loading condition to produce a multiaxial stress field for validating the load carrying capability. Based on the microstructure of the composite laminates reinforced by non-crimp unidirectional carbon fiber fabrics, specimen of biaxial compression was designed and followed by the testing under uniaxial and biaxial compression as well. Comparative analysis was also carried out for the mechanical behavior of the composites reinforced by unidirectional carbon fiber fabrics under different compression loads. The results show that the composites performs linear compression behavior and brittle fracture, and the failure mechanism of composite is overall represented as shear buckling under uniaxial compression. Compared with uniaxial compression, although the composites still performed linear compression behavior and brittle fracture under biaxial compression, its stress-strain curves showed some nonlinear characteristics. The strength of composites under biaxial compression was much lower than that of the uniaxial compression results. Resistance to deformation of the composite was enhanced when the biaxial compression loading was kept at 1∶1, resulting in the increasing of the compression modulus. The result was opposite while the biaxial compression loading was kept at 2∶1. The failure mechanism of the composite was basically the same when the biaxial compression loads were kept at 1∶1 and 2∶1, mainly as matrix cracking, fiber breakage and interlaminar debonding. Especially, the phenomenon of interlaminar debonding was obvious.