Ignition characteristics of the mixtures of Al powder and pure RDX, HMX and CL-20 are studied by using CO2 laser with a wavelength of 10.6 μm, and the effects of the Al granularity, the ratio of Al to RDX and different explosives of the mixtures on ignition characteristics of the mixtures are discussed under different laser heat fluxes. The results show that the ignition of the mixtures tested appears on the surface of the sample, and the ignition time delays of the mixtures gradually decrease with the increase of the laser flux. The effects of Al granularity and the ratio of Al to RDX on the sample igintion are larger at lower laser fluxes and slightly weaken with the laser flux increasing. The delay time of the mixture containing aluminium nano-powder is shorter than that of the mixture containing aluminium micro-powder, and the ignition process is more drastic. The order of the delay time of the mixtures of nano-alumimium with RDX (M-QR), HMX (M-QH) and CL-20 (M-QCL) is tM-QR>tM-QH>tM-QCL and the order of the minimum ignition energy is EM-QR>EM-QH>EM-QCL which is defferent from the order of RDX, HMX and CL-20 that is EHMX