Abstract: In order to reduce the laser initiation energy and understand effect of laser wavelength on initiation sensitivity of explosives, the weak chemical bond and sensitive laser wavelength of PETN, RDX, HMX and HNS explosives were analyzed through spectrum, thermal decomposition mechanism and quantum mechanics calculation. Results show that the weakest chemical bond of PETN, RDX, HMX and HNS are nitryl whose correspondent resonant coupling laser wavelength is around 6300nm,and the laser wavelength inducing electronic transition of PETN, RDX, HMX and HNS explosives is among 190nm~250nm. Under the action of laser at these characteristic wavelengths, laser initiation energy of explosives can be decreased.