Because of the imperfect theoretical model and insufficient experimental verification technologies, the problem of information transmission in the plasma sheath has not yet been resolved. In this paper, the interaction mechanism between X-ray photons and plasma is studied firstly, and a modified theoretical model is provided through numerical calculation and theoretical modeling. Different from the conclusion that X-rays can penetrate plasma without attenuation in the traditional wave model, the modified theoretical model established in this paper points out that the transmittance of X-rays in plasma is closely related to plasma electron density and incident X-ray flux. Secondly, an experimental system was built using a grid-controlled X-ray modulation emission source, a single-photon X-ray detector, and a dynamic plasma generator. Using this system, the non-uniform plasma which electron density ranges from 10⁹/cm³ to 10¹⁴/cm³ is generated, and the X-ray communication with 1 Mbps communication rante and 10^-5 bit error rate is also verified. The experimental results indicate that the modified theoretical model can explain and predict the experimental phenomena, and the experimental system can provide the solution for solving the communication problems in the plasma sheath.