ABSTRACT With the increasing application of high‐performance composite materials in various fields, fiber‐reinforced epoxy composites will witness tremendous development. Basalt fiber is an environmentally friendly fiber with high performance, but the high density restricts its application in flying equipment. In this work, different numbers of carbon fiber cloths were used to replace the basalt fiber cloths in the middle of the composites to reduce the density and to probe the influences of carbon fiber cloths. It was found that carbon fiber cloths can effectively reduce the density of the composites, but the curing degree and thermal resistance decreased slightly. As the carbon fiber layer increased, the mechanical properties of the composites decreased and then increased. When 4 layers of carbon fiber cloths were introduced, the composite basalt fiber: carbon fiber = 6:4 (6B4C) showed the lowest density of 1.737 g/cm 3 , 0.222 g/cm 3 lower than basalt fiber: carbon fiber = 10:0 (10B0C). Moreover, 6B4C possessed the highest flexural strength of 804 MPa and shear strength of 54 MPa.