Boron-potassium nitrate is an important energetic material, whose ignition and burning performances depend on the oxygen/fuel ratio closely. The laser ignition of B-KNO3 composites and doped composites by phenolic resin at different oxygen/fuel ratios were experimentally studied, thermodynamically calculated， and thermally analyzed. The laser ignition process consists of laser ablation, thermal chemical reaction， and combustion. The laser ignition threshold of 50% fire has minimum of 7.6 mJ (B-KNO3:50/50) and 4.05 mJ (B-KNO3-phenolic resin:40/50/5) with the increase of boron fraction from 30% to 70%. The laser ignition delay time decreases with the laser energy density linearly, moreover the composite of lower laser ignition threshold also has shorter ignition delay time. Because of the onset temperature of reaction of B-KNO3 from 556 ℃ to 548 ℃ and released heat from 1.86 kJ/g to 2.21 kJ/g in case of admix of phenolic resin to B-KNO3, its laser ignition sensitivity and ignition delay time becomes higher and shorter respectively.