Highly pure Cr2AlC powder was synthesized by microwave hybrid heating a Cr/Al/Cr3C2 powder system in the temperature range of 700-1050 ℃ in argon atmosphere. The effect of sintering temperature and constituent on the synthesis of Cr2AlC were studied. By XRD, SEM, DSC, the phase assembly, microstructure and reaction mechanism of samples were analyzed. The results indicated that by microwave hybrid heating,when the molar ratio of mixtures powders 1Cr3C2/2.2Al/1Cr, high pure Cr2AlC powders were obtained at 1050 ℃. When the component Al excess 10at%、20at%、40at%, Cr2AlC with small amount of Cr7C3 were obtained. The amount of Cr2AlC phase was gradually increased by the reaction between Cr-Al intermetallic compounds, un-reacted Cr and Cr3C2 in the temperature range of 700-1000 ℃. And it become a pure phase in the sample with disappearance of intermediate phase at 1050 ℃ for 3min,and the particle size of about 5-8祄.