Abstract: ObjectiveIn order to provide theoretical references for development and applocation of Mosla dianthera, the antifungal activity and chemical constituents of essential oil from M. dianthera in Jigong Mountain of Henan were investigated. MethodEssential oil was extracted from M. dianthera by steam distillation, and through fumigation, its inhibitory effects on four plant pathogenic fungi namely Botrytis cinerea, Fusarium graminearum, Rhizoctonia solani and Sclerotinia sclerotiorum were studied by determining growth rate. Meanwhile, chemical constituents of essential oil were analyzed by GC-MS. ResultEssential oil from M. dianthera showed strongly inhibitory effect on growth of four target plant pathogenic fungi , and its 50% effective concentration ( EC50 ) was less than 10 μL/dish . Twenty-two chemical constituents were isolated from essential oil, and 20 of which were identified, accounting for 98.822%of total essential oil. The main chemical constituents of essential oil were eucalyptol(64.684%), β-pinene(7.963%), 1,3,6-octatriene,3,7-dimethyl-,(Z)-(5.239%), and β-phellandrene(4.673%) etc. ConclusionThrough fumigation, essential oil from M. dianthera in Jigong Mountain of Henan shows strongly inhibitory effect on plant pathogenic fungi, which is used as a fumigant for controlling plant disease in the future.