Abstract: Cobalt ferromagnet/carbon and nickel cobalt copper ferromagnet/carbon nano composite were prepared. Infrared and ultraviolet-visible spectra were tested in range of 2.5-25 m and 200-800 nm, while the extinction coefficients were calculated by using Lambert-Beer law. The extinction coefficients of cobalt ferromagnet/carbon composite, especially nickel cobalt copper ferromagnet/carbon composite increased after calcination. Nickel cobalt copper ferromagnet/carbon composite attained at 0.36 m2g-1 and exceeded 0.15 m2g-1 in the range of 3-16 m. When the ratio of Nickel cobalt copper ferromagnet/carbon composite to acetylene black is 5:1, the extinction coefficient of the mixture reached 1.25 m2g-1 and exceeded 0.90 m2g-1 in the range of 3-5 m and 8-14 m. For ultraviolet-visible band, both cobalt ferromagnet/carbon composite and nickel cobalt copper ferromagnet/carbon composite exhibited show excellent extinction property. The different of main mechanism between infrared and ultraviolet-visible range were discussed. The reflectivity curves were test by adopting Arch Method in the range of 2-18 GHz. Mixing ferromagnet/carbon composite, the reflectivity curve of FeNi/carbon fiber moved to lower frequencies, as well as the absorbing bandwidth broadened.