The invention discloses an offshore fan pile foundation design method and application thereof. According to the offshore fan foundation design specifications and the offshore fixed platform design specifications, design calculation analysis is carried out based on ocean engineering design analysis software structural analysis computer system (SACS). The design calculation analysis comprises a fundamental analysis, a modal analysis, a seismic analysis, an ice load analysis, a hoisting analysis, a transportation analysis and an installation analysis. Through the method, actual environmental conditions of offshore fans are totally considered in the method, the analyses are accurate, results are reliable and design efficiency is high. Meanwhile, all aspects of foundation design, hoisting, transportation and installation of the offshore fans are considered in the design method. Therefore, the offshore fan pile foundation design method has the advantages of systematicness and comprehensiveness, and can be applied to intertidal belt fan pile foundation design.