In this study, analytical study to improve structural safety of the CFMP (Concrete Filled MultiPiles) based offshore wind hybrid substructure system was carried out. Firstly, in order to optimally arrange the multi-piles at the upper part, diffraction analyses were carried out for the three multi-piles arrangement cases. Then, in order to minimize wave-induced bending moment at the substructure, diffraction analysis and structural analysis were carried out for the four cases substructure system of a mono-pile and three hybrid cases. As the results of diffraction analysis for the three multi-piles arrangement cases, maximum wave force of five multi-piles case indicated about 30% lower level than that of mono-pile case. Therefore, multi-piles arrangement of hybrid substructure was decided as five multi-pilescase. As the results of bending moment calculation at the critical bending points, wave-induced bending moment of hybrid cases decreased about 75.3 ~ 79.4 % for the extreme wave loading. Integrated bending moment of three hybrid cases including windinduced bending moment decreased about 18.8 ~ 24.6 % comparing with the mono-pile case. As the results of bending moment calculation at the foundation pile head, integrated bending moment of the concrete base height 8.0 m was similar with the mono-pile and of the concrete base height 6.0 m decreased about 4.4 %, respectively. Therefore, in order to certify the same level of the structural safety for the hybrid substructure of this study, it was found that the critical height of the concrete base was the 8.0 m. In this case, structural safety at the foundation pile has the same level with the mono-pile case. However, structural safety at the multi-pile (upper) part has the enhanced safety level comparing with the mono-pile.