This invention discloses a defect isolation method for thin-film solar cell having at least a defect therein. The thin-film solar cell comprises a substrate, a front electrode layer, an absorber layer and a back electrode layer stacked in such a sequence. The defect isolation method includes the steps of: detecting at least a defect formed in thin-film solar cell and acquiring the positions of the defects, and applying a laser light to scribe the outer circumference of the defects according to the positions of the defects so as to form at least an isolation groove having a closed-curve configuration.