Abstract: The existence of salt content in turbine exhaust may change the dielectric properties of the wet steam, and may subsequently affect the wetness measurement results. The influence of electrical conductivity on both the dielectric properties of wet steam and the wetness measurement precision were quantitatively analyzed by introducing the electrical conductivity into the pure steam complex permittivity formula and the wetness measurement formula. Results show that the real part of the complex permittivity increases with rising microwave wavelength, conductivity, wetness and temperature, whereas the imaginary part first increases and then decreases with the rise of microwave wavelength, which increases with rising conductivity, wetness and temperature; the measurement deviation of steam wetness increases with rising conductivity and wetness, and with reducing temperature and working frequency. The existance of salt content in turbine exhaust has little effect on the complex permittivity, when high precision may be achieved in the wetness measurement.