It has been a hotspot to looking for high performance electromagnetic attenuation material. At present, the conventional inorganic materials, such as aluminum foil, copper, graphite, have been widely used in electromagnetic attenuation field. However, there are certain restrictions on the use of inorganic materials, such as high cost of raw material, low generating efficiency, and environment unfriendly. Recently, considerable attention has been paid to microbial materials, which has the potential to solve the problems above. In this study, three biological materials, fungi An0429 spores, fungi Bb0919 spores and fungi Cx0507 spores were used to measure infrared extinction performance. They were subjected to specular reflection spectra measurements in the range of 4 000～400 cm-1 (2.5～25 μm) by squash method. The real (n) and imaginary (k) parts of the complex refractive index of biological materials were calculated by using Kramers-Kroning relation based on the measured data. The complex refractive index with real part n and imaginary part k in the infrared band satisfies the following conditions n≥1 and k≥0. The static mass extinction coefficient was calculated based on Mie theory. Compared with common inorganic materials, biological materials possess a good extinction performance. In the smoke box test, the transmittances of fungi An0429, fungi Bb0919 spores and fungi Cx0507 spores were 5.1%, 8.2% and 7.4%, the mass extinction coefficients were 1.257, 1.065 and 1.009 m2·g-1. These results showed that have higher extinction characteristics. In addition, biological microbial materials have other advantages, such as short growth cycle, low production cost, absence of toxic in the casting process, and environmental friendliness. Therefore, microbial materials have great potential in extinction applications.