In this paper, the theoretical model of ununiform plasma sheath is established based on scattering matrix method and the transmission characteristics of 0.1 THz～10 THz wave are simulated. A kind of plasma jet is produced in laboratory environment according to the principle of dielectric barrier discharge. Then the measurement of transmission spectrum of terahertz time-domain spectroscopy (THz-TDS), broadband terahertz source, and the terahertz wave reflective imaging of target under plasma shelter are carried out, respectively. Both theory and experiment results show that terahertz wave has good penetration in plasma, which provides a new way for communication and radar detection in blackout area.