Abstract: Using a parameterization method of site errors estimation in lightning locatiag system (LLS) and the real data observed by a LLS consisted of three direction finders (DFs) in Beijing region, the site error correction curves for all DFs for 1988 and 1989 respectively are obtained.The result shows that the curves, as a function of measured bearing, not only include the even-sinusoidal component but also the odd one.It also indicates that the site error correction curves are stable v,ia time, For discussion, we propose that the stimulated radiation of dipole isprobablely the dominant factor which can produce serious site errors, and a mathmatics model for Site errors due to dipole radiation is developed,This model can be used to explain reasonably the characteristics of structure of site errors.