Carbon nanomaterials is a new kind of materials with good qualities such as small dimension,light weight,good characteristic of electrical conductivity and electromagnetic wave absorption etc. To explore the applications of carbon nanomaterials on interference the imaging IR guidance weapons,using large smoke chamber,the shielded extinction performance for IR images of carbon nanotubes,carbon nanofibers,nanographite were tested in the wavelength range of 8-12 μm. Results show that carbon nanomaterials smoke has excellent far infrared extinction capacity,the minimum and the maximum of far infrared extinction coefficients are 0.8884 m²·g^-1 and 2.6226 m²·g^-1 respectively.