The invention discloses a large phased array antenna accurate installation method based on mathematical modeling, is suitable for single-wing or double-wing large phased array antenna accurate installation and adjustment and measurement of large size and high requirement of installation accuracy, and belongs to the field of microwave remote sensing general installation design. The method comprises the steps that (1) a star coordinate system is established; (2) fine adjustment of the star attitude is performed; (3) the coordinates of the installation points on the antenna and the start are measured; (4) a mathematical model is established and a gasket is calculated and adjusted; (5) the gasket is additionally arranged to install the antenna according to the calculation result; and (6) the planar integrated direction is measured and the gasket is corrected. The problems of the influence of repeated trial installation and adjustment of the large phased array antenna on the antenna installation accuracy and efficiency can be avoided so that the method has the advantages that project implementation is high, the installing accuracy can be easily guaranteed, the frequency of installation and adjustment and accurate measurement can be reduced and the installation efficiency can be enhanced.