Laser ignition characteristics of double-based (DB) propellant SQ-2 and RDX-CMDB propellants were studied by CO₂ laser ignition at different laser fluxes. The effects of content of RDX,Al powder and burning catalysts on ignition characteristics of RDX-CMDB were discussed. Results show that the laser ignition delay time of DB propellant SQ-2 and RDX-CMDB propellants except the sample containing Al powder becomes shorter with the heat fluxes increasing,and its change slows down. The influence of the content of RDX,the additives of Al powder and the burning catalysts on the ignition delay time was related with the laser fluxes. The content of other components had little effect on the laser ignition delay time of propellants. Al powder could prolong the delay time at lower heat fluxes,and the delay time increased with increasing of the content of RDX，and Al powder and the catalysts in the propellant had both great influence on the laser ignition process and the delay time of the propellants at the higher heat fluxes.