The invention relates to a method for precisely positioning a navigation mark and determining whether the navigation mark is within a reef danger zone, and the method belongs to the field of shipping. The method comprises the steps that: navigation mark equipment obtains position information during positioning; the navigation mark equipment uploads the obtained position information to a positioning deviation rectification server; the positioning deviation rectification server obtains a base station position from a base station trusted position table according to a base station serial number, and obtains a WIFI position from a WIFI trusted position table according to WIFI fingerprint information; the positioning deviation rectification server judges whether a GPS position (obtained when a navigation mark terminal is positioned) deviates by utilizing the obtained base station position and WIFI position, and performing deviation rectification if GPS position information deviates; the positioning deviation rectification server transmits a precise position after deviation rectification to the navigation mark terminal; and whether the navigation mark is within the reef danger zone is determined through combining the position after deviation rectification. The method solves the problem that the conventional GPS has large positioning errors and cannot warn that the navigation mark deviates from the reef danger zone timely and precisely, and is conductive to guaranteeing safe navigation of the fairway.