Abstract: The unique structure of carbon nanotubes (CNTs) has prompted intensive study for special electromagnetic properties. For the multiwalled carbon nanotubes(MWCNTs)，the research work on electromagnetic properties is seldom reported. In this work，MWCNTs/glass fabrics (GF)/epoxy (EP) composites were produced by selecting the glass fabric as carriers to help MWCNTs to disperse. Then the permittivity，magnetic conductivity，reflection loss，electrical conductivity and morphology of the composites with different contents of MWCNTs in the wave band from 26.5 to 40 GHz were researched respectively. It is found that the real part and imaginary part of permittivity increase with the content of MWCNTs. Especially for the dielectric loss tangent，it has been increased by four times. However，the magnetic conductivity  stays around the level of one (μ=1) and the composites present less magnetic properties. Moreover，the MWCNTs/GF/EP composite can be changed from the insulator to the semiconductor along with increasing the content of MWCNTs. In the electromagnetic wave band (26.5～40 GHz)，the effect of absorbing is not satisfying for the MWCNTs/GF/EP composites.