Abstract: Aiming at the problem of determining shadowing location and the date by shadow change of shadow in sun shadow position technology,this paper determines the rule of variation of shadow length about object height,longitude and latitude,and solar altitude angle by analyzing various factors that effect shadow length of object.Based on the least square principle,a nonlinear programming model is established,which is based on the minimum error between the length of shadow and the calculated shadow.The initial value is selected by curve fitting,and the results are searched by exhaustive algorithm.For videodate positioning problem,the captured video is preprocessed by extracting the frames at a fixed frequency.After obtaining the measured data,the model is used to realize the positioning analysis of the video data.