The ignition threshold of laser supported detonation wave (LSDW) of aluminum generated by 1064 nm and 355 nm laser pulses is studied using acoustic method. The relation between the pressure of laser-induced plasma acoustic wave and the expansion velocity of shock wave is analyzed theoretically. Then the experimental research of aluminum target irradiated by the laser with the wavelength of 1064 nm and 355 nm is developed. The experimental results show that the lifetime of plasma acoustic wave is on the millisecond order, and the peak intensity of plasma acoustic wave decays exponentially. It is found in the experiment that the signal amplitude of plasma acoustic wave generated by the laser irradiation on aluminum target increases with laser power density increasing. However, the peak intensity of plasma acoustic wave appears jump stage twice while laser power density increases. From this it can be determined that the ignition threshold range of LSDW is (3.95～13.05)×108 W/cm2 for 1064 nm and (3.14～10.07)×108 W/cm2 for 355 nm laser pulse. Furthermore, the wavelength effect on the ignition threshold of LSDW is analyzed.