To explore the potential roles of oxalic acid (OA) in the pathogenesis of Sclerotina sclerotiorum,we sprayed 30 mmol/L OA evenly onto 3-week-old Arabidopsis and found AtWRKY63 was markedly induced by OA.To further elucidate the function of AtWRKY63,we obtained pure line of AtWRKY63-overexpression Arabidopsis by constructing AtWRKY63-overexpression vector and transforming Arabidopsis.The Arabidopsis plants overexpressing AtWRKY63 showed enhanced resistance to S.sclerotiorum.Histochemical staining revealed that overexpression of AtWRKY63 induced oxidative burst in host plants,which suppressed the hyphal growth of S.sclerotiorum,and consequently inhibited fungal infection.qRT-PCR analysis indicated that AtWRKY63 may involve in salicylic acid-dependent and jasmonic acid-dependent defense signaling pathway,thus,confers the resistance to S.sclerotiorum.