The absorption spectra of HNS, in the frequency range of 0.2-4.0 THz, were calculated by using quantum chemistry calculation method,and the theoretical calculation results show that the characteristic peaks of HNS are located in 1.9 THz and 3.3 THz. The experimental results offered by THz time-domain spectroscopy technology and FTIR show that the characteristic peaks of HNS are located in 1.7 THz and 3.1 THz. The experimental results agree with the theoretical calculation results, which show that HNS has distinct characteristic absorption peaks in the frequency range of 0.2-4.0 THz.