There are about 16 spectral lines emitted from discharge initiated non-chain pulsed HF laser, covering from 2.65 μm to 3 μm, when the laser is working in full spectrum output. The absorption of H2O molecules at about 2.7 μm in air has a great influence on the laser pulse energy. The absorption attenuation rules of wide spectral band pulsed HF laser in air are obtained by using discharge initiated non-chain pulsed HF laser. The experimental results show that the absorption coefficient is about 0.066 m -1 just at the output window of the laser device in full spectrum output, and then decreases to around 0.01 m -1 after 40 m propagation. The absorption attenuation coefficient reduces when the propagation distance increases, and tends to be constant. By suppressing the laser wavelength below 2.8 μm of non-chain pulsed HF laser, the attenuation coefficient is reduced to about 1/3 of the value obtained before at the output window, i.e., about 0.022 m -1, and the attenuation of laser energy by air absorption is reduced to some extent.