On the ground-to-air link wireless optical communication link, the cloud layer is one of the main factors affecting the scattering characteristics of laser transmission. The cloud layer is mainly composed of water droplets, ice water or other mixed core-shell ice crystals. In this paper, a 2, 8 and 39 spherical core-shell structure agglomerated ice crystal sub-models were established considering the crystal nucleus and intermediate mixed layer structure, and the influence of crystal nucleus size on the ice extinction, absorption and scattering coefficients of ideal agglomerated core-shell structure was analyzed. By comparing the refractive index of the uniform mixed layer, the scattering intensity of the three kinds of multi-spheroidal ice crystals with pure ice crystals, ideal core shell and core shell considering the intermediate mixed layer was compared with the scattering angle. The numerical results show that the ideal core-shell structure and the core-shell structure of the intermediate mixed layer have great influence on the scattering characteristics of ice crystal particles. Under the same conditions, there are significant differences in the extinction, absorption and scattering coefficients of ice crystal grains in three different agglomerated core-shell structures. The results of this study are more accurate in the study of the scattering characteristics of ice crystal particles, which lays a theoretical foundation for the transmission analysis of wireless optical signals in random distributed ice clouds.