Abstract: Magnetic property change of the Co-based amorphous glass-covered wire before and after glass cover removal was investigated by AC hysteresis loop.Noise suppression film materials containing Co-based amorphous glass-covered wires were prepared.S parameters of the composite film were measured by microstrip measurement system.Power loss ratio was figured out through the S parameters.Influence of glass cover on microwave noise suppression effect of the composite films was investigated.The results show that the coercivity of the as-prepared amorphous glass-covered wire is larger than that of the wire after glass cover removal at the frequency of 5 kHz.The reflection of the composite film at lower frequency increases due to glass cover removal,while the reflection at higher frequency decreases.The absorption of the composite film at lower frequency increases,and the absorption peak becomes wider.The width of the stop band increases obviously and noise suppression effect gets strengthened when the glass cover of the wires is removed.The composite film containing wires after glass cover removal has excellent noise suppression effect,which power loss ratio is above 80% between 1.8Hz and 8.5Hz.