Research on lightweight advanced materials that combine heat insulation and sound isolation becomes more attractive day by day. In this study, a 3D spacer structural Kevlar/polyimide composite (3DSSK/PIC) with light weight, heat insulation and sound absorbing properties was prepared by a combination of structural design, hand paste resin method and hot-pressing process. The fabricated 3DSSK/PIC possesses more than 80% of void as well as the ultra-light density (0.2 g/cm3). Consequently, the thermal insulation performance of 3DSSK/PIC (34%) is superior to that of polystyrene foam (adiabatic ratio ΔT ~20%) and similar to that of wood block (ΔT ~35%). Furthermore, the sound absorption coefficient of the 3DSSK/PIC is higher than 0.2 in the range of 600 ~ 2500 Hz, demonstrating its super sound absorption performance. In addition, compressive tests and SEM images were conducted to characterize the mechanical and structural performance. Therefore, the ultra-light 3D fabric reinforced composite with ultra-high thermal insulation and sound-absorbing properties justify a great potential in a wide variety of applications in the industry engineering, automobile, or aerospace.