Hybrid　Ti3SiC2　and　carbonyl　iron　powders　were　composited　with　epoxy　and　polyamide　resin　to　fabricate　thin　thickness　and　wide　bandwidth　microwave　absorption　composites.　The　influences　of　Ti3SiC2　content　and　particle　size　on　the　complex　permittivity,　complex　permeability　and　microwave　absorption　properties　were　investigated　systematically　in　the　frequency　range　of　8.2-12.4GHz.　It　was　found　that　the　real　and　imaginary　parts　of　complex　permittivity　were　improved　obviously　by　increasing　Ti3SiC2　content　or　decreasing　Ti3SiC2　particle　size,　which　are　ascribed　to　the　enhanced　interfacial　polarization　and　conductance　loss.　By　calculating　the　reflection　loss,　the　composite　with　7vol%　Ti3SiC2　content　and　＜　30　mu　m　Ti3SiC2　particle　size　exhibited　a　wide　effective　absorption　bandwidth　of　3.6　GHz　in　8.8-12.4　GHz　when　the　thickness　is　1.2　mm.