M-type strontium ferrite powders were prepared by sol-gel-autocombustion and the micro-structures, morphology and the electromagnetic properties of powders were characterized. Impedance matching solution maps was designed to obtain the matching frequency and the matching thickness. Based on the match-ingfrequency and the matching thickness, microwave absorption of the material was studied. The results show that with increasing of temperature the shape of particles change from rice-like to hexagon. It is found that an-nealing temperatures could affect the microwave absorbing properties of SrFe12O19. When annealing tempera-ture is 1000℃ with a 5.2 mm thickness, the maximum reflection loss becomes - 38 dB at 6 GHz, and the - 5 dB bandwidth reaches 4.5 GHz.