In order to accurately monitor the changes of wet steam parameters in steam turbine,and to improve the internal dehumidification technology and unit operation efficiency,a backward non-coaxial scattering model for the measurement of wet steam parameters was optimized and tested so that.Based on the Mie scattering theory,the wet steam measurement model was established,and the geometric model of the original scattered was optimized.The measurement model was simulated by MATLAB,and the results show that the scattered light intensity value is optimal when the receiving distance d=0.32 m,the water droplet mass median radius r0.5 =1 μm,the size distribution parameter K= 5 and the water droplet concentration N= 2.5 × 1011.The CCD camera signals were extracted and processed by a subtractive extinction method and a mean filtering method.The experimental measurement and inversion of wet steam parameters under different working conditions were carried out.The results of experimental inversion and that of simulations have a consistent change trend.The results verify the accuracy of the CCD-based backward non-coaxial scattering measurement model and the feasibility of experimental study on measuring the steam humidity in steam turbine,which provides a scientific basis for future measurement of turbine steam humidity.