Due　to　the　complexity　of　the　medium　composition,　physical　characteristics　and　the　spreading　of　electromagnetic　waves,　the　extraction　and　automatic　target　detection　of　the　Ground-penetrating　Radar　(GPR)　is　extremely　complicated　and　has　become　an　important　issue　in　the　practical　application　of　GPR.　In　this　paper,　a　method　based　on　curve　fitting　is　proposed　by　using　the　hyperbolic　echo　characteristics.　The　edge　lines　of　GPR　images　firstly　obtained　by　using　image　preprocessing　methods　and　hyperbolas　are　fitted　to　approximate　the　edges.　Finally,　hyperbolic　echo　apex　positions　in　the　GPR　images　are　extracted　and　marked　on　their　apexes.　The　experimental　results　show　that　all　targets　are　detected　correctly.　©2010　IEEE.