The composite structures with lightweight, excellent mechanical and thermal properties are crucial to apply in the fields of industrial, civil as well as aerospace engineering. In this study, three-dimensional glass woven spacer fabric-reinforced epoxy resin composites (3DWSCs) were designed and manufactured. By increasing the interlacement of the pile yarn (IPY) from 2 to 6 ends/cm, the 3DWSCs presented similar light densities (0.3-0.42 g/cm(3)) but significant improvement in specific strength was from 3.9 to 24.6 MPa g(-1) cm(3), which is much higher than that of other reported 3DWSCs. This was because the pile yarns in the 3DWSC with dense IPY structure (6 ends/cm) were connected and supported with each other, and thus, their strength was fully utilized during compressive process. Contrary to the compressive strength, with the IPY increasing from 2 to 6 ends/cm, the thermal insulation of the 3DWSCs exhibited limited variation (~ 12.5%) and showed comparable performance with wood due to its high percentage of hollow structure (~ 75%). Therefore, the optimal 3DWSC structure (IPY is 6 ends/cm) with connected pile yarn structure exhibited excellent compressive strength as well as good thermal insulation, which showed great potentials in practical applications.