As an important component of space environment, the ionospheric plasma is the main background environment for the operation of low-orbit spacecraft. The study of ionospheric plasma environment parameters and the enrichment of plasma environment data are beneficial to improve the reliability of low-orbit spacecraft operation. Langmuir probe is the most popular method for detecting the plasma parameter of ionospheric, however, it has some defects. In this paper, we design a plasma generator based on radio-frequency discharge to imitate the ionospheric plasma environment, and measure plasma parameter based on Thomson scattering by import a Nd: YAG laser oscillate in the plasma generator. The result demonstrates that the intensity of laser Thomson scattering signal is positively correlated with the change of plasma electron density. The electron density in the plasma generator is calculated according to the laser Thomson scattering signal intensity, and the error is less than 10% compared with that measured by the Langmuir probe.