Wind power-to-hydrogen from offshore is an important pathway to utilize far offshore wind resources. Distributed wind power-to-hydrogen units have become the focus of academic research and industry practice because they does not need centralized confluence and large-scale platform construction. However, affected by the wake effect of the wind farm, different units in the distributed wind power-to-hydrogen clusters operate coupled to each other, resulting in differences in hydrogen production ability. This paper proposes the optimal capacity model of the distributed wind power-to-hydrogen considering the wake effect. Optimal configuration of electrolytic cell capacity space distribution is carried out based on unit collaborative control. The realistic wind resource data of the waters of Jiangsu Province in China is adopted for case studies. First, the collaborative control of wind power-to-hydrogen units considering the wake effect can effectively increase the annual expected hydrogen production by about 3.05%. Furthermore, compared with the uniform distribution scheme of electrolytic cell capacity space, the optimal configuration scheme of capacity space with large margin and small interior can reduce the levelized cost of hydrogen for offshore wind power-to-hydrogen, which verifies the effectiveness of the proposed optimal model.