The aim of this study is to determine the maximum number of berths in some sea area under the condition of ensuring navigation safety and service level,namely the capacity of yacht docks.Firstly,the number of yacht that some sea area can simultaneously accommodate,namely the capacity of sea area,is calculated by establishing mathematical models.Then the capacity of yacht docks is calculated according to the proportion of trip of yachts.This study establishes two models to calculate the capacity of sea area:1) safety distance model based on navigation safety,which is proposed by mathematical analysis；2) computer simulation model based on analysis of service level.The capacity of yacht docks at Daya bay,in the city of Huizhou,is calculated as a case,based on both safety distance model and computer simulation model.This study proposes theoretical model to analyze capacity of yacht docks and provides guidance for the planning and design of yacht harbor.