The invention discloses a method for generating a line element buffer zone on an earth elliposoid based on a GIS (geographic information system) component. The method comprises the following steps of: a, determining vertexes of line elements on an encrypted earth elliposoid; b, calculating out geodetic circles; c, calculating out geodetic rectangles; and d, adopting a CIS component to perform union set generation on the geodetic circles and rectangles established in the step b and step c, so as to obtain a polygon, namely a line element buffer zone on the earth elliposoid. By the method in the invention, the process for generating a line element buffer zone on the earth elliposoid is greatly simplified, and a convenient and efficient method for generating a line element buffer zone on the earth elliposoid on any map projection plane can be provided for users having GIS secondary development capability, an effective technical means for generating high-precision unilateral and bilateral ocean boundaries can be provided for ocean demarcation, and the method has an important significance on protecting national ocean rights and interests according to laws.