To solve the problem of high toxicity and poor consistency of traditional beryllium oxide microwave attenuation ceramics, a kind of environment-friendly AlN-FeSiAl microwave attenuation ceramics based on aluminum nitride with high thermal conductivity was developed in this paper. The material is added FeSiAl to the AlN matrix and belongs to environment-friendly material. In order to obtain high thermal conductivity and good electromagnetic performance, the effects of different aluminum nitride powders, FeSiAl additive amount and sintering process on composite properties were studied. The results show that adopting Toyo aluminum nitride, adding 10 wt% FeSiAl, vacuum hot pressing sintering under 1650 ℃ and 85 MPa, the high attenuation performance of microwave attenuation ceramics is realized, and material thermal conductivity is 88.2 W/(m.K), close to that of the microwave attenuation ceramics based on aluminum nitride in Ceradyne company.