Pupil　detection　is　the　key　technology　for　improving　the　automation　of　fundus　camera.　Aiming　at　the　problem　of　low　pupil　detection　accuracy　under　large　occlusion　condition,　an　accurate　pupil　detection　method　based　on　ellipse　fitting　and　parameter　passing　is　presented.　Firstly,　down-sampling,　binarization,　maximum　connected　region　and　sweeping　line　methods　are　introduced　to　realize　the　extraction　and　patching　of　the　pupil　area.　The　spurious　edge　point　eliminating　algorithm　based　on　closed　edge　detection　is　presented　to　improve　the　ellipse　fitting　accuracy,　and　the　pupil　parameters　are　obtained　using　ellipse　fitting　algorithm　combining　with　least　square　method.　Finally,　the　pupil　parameter　correction　algorithm　based　on　inter-frame　parameter　passing　is　presented　to　correct　the　pupil　parameters.　Experiment　results　show　that　compared　with　existing　methods,　the　proposed　single　frame　image　pupil　detection　method　could　obtain　the　pupil　parameters　quickly,　and　the　pupil　parameter　correction　algorithm　could　improve　the　pupil　parameter　accuracy　under　large　occlusion　condition.