We reported a rare case of sudden onset of severe but reversible suprachoroidal air that occurred at the moment of air-fluid exchange in 23-gauge vitrectomy. A 31-year-old male patient presented with a large break at 10-11 o'clock and high bullous, nearly total retinal detachment. He underwent first surgery with silicon oil injection at the end of the surgery. He was arranged to have a second surgery for silicon oil removal through pars plana vitrectomy which was performed smoothly at first. While switching to another mode of air-fluid exchange to clean the residual emulsified oil droplets, surgical view disappeared completely and was suddenly replaced with severe and total suprachoroidal air, which fortunately resolved within 3 days without any other severe complications.