The invention relates to an STL (standard template library)-based analysis method on the sheltering to a solar wing by a communications satellite large antenna, and belongs to the technical field of satellite design. The invention provides a method which can effectively analyze the sheltering to the solar wing by the large antenna according to a satellite orbit dip angle and attitude offset, and comprises the steps of firstly, converting a three-dimensional model of an object to be analyzed into an STL data file, secondly, extracting an effective triangular net in solar wing battery piece STL data, thirdly, performing interpolation processing on the triangular net of a solar wing battery piece, fourthly, processing large antenna STL data and then projecting the large antenna STL data to a plane where the solar wing battery piece exists, fifthly, judging the sheltering condition of the battery piece and the triangular net of the large antenna in a two-dimensional plane, and sixthly, computing the sheltering area according to the sheltering condition and generating an analysis graph. The method can obtain the sheltering condition of the large antenna to the solar wing at any moment, is convenient for a power supply and distribution designer to perform intuitive analysis, simplifies the computing process, and is convenient for project implementation.