In this paper, Multi-walled carbon nanotubes (MWCNTs) and TiO2 were mixed by ball milling to obtain composite powders. The composite powders were characterized by XRD, SEM and network vector analyzer. The absorbing properties of composite powders in space were analyzed by theoretical calculation using numerical model. The results show that the dispersibility of MWCNTs in the MWCNTs/TiO2 compositepowders with anhydrous ethanol wet mixing is better. Wet-mixed MWCNTs/ TiO2 composite powders have better impedance matching characteristics and spatial absorbing ability in 2~18GHz band, which provides theoretical reference for the practical application of composite absorbing materials.