In order to accurately measure the steam moisture and droplet size, a new method is proposed to measure the light scattering in steam turbine, and by optimal numerical fitting, we can get the value of steam moisture distribution and droplet size. According to the characteristic of CCD imaging and light scattering theory, the experimental platform including the measurement system and simulation system of steam turbine is set up. The laser with the wavelength of 532nm is adopted to irradiate the moisture gas, and the light scattering distribution by the scale of 2.6°～6.6° is measured by CCD, so the steam moisture distribution(0.7%~1.2%) and average droplet size(1.4 ~1.6μm) can be calculated by curve fitting. The experimental results indicate that this method can be used to measure steam moisture and droplet size, and the large scale can be achieved by using CCD. Furthermore, the experimental results also vividly reflect the varying rule of steam moisture and droplet size, so the feasibility of application of CCD technology in measure of steam moisture is supported strongly.