The repellent activitie of Cinnamomum japonicum oil against Aedes albopictus were investigated. The main volatile chemical components of the oil were qualitatively studied. The main results are given as follows. Cinnamomum japonicum oil providing absolute protection against Ae. albopictus in laboratory and field for 2.33 ± 0.63 h, 3.85 ± 0.21 h at concentration of 1.5 mg/cm2, respectively. A total of 28 compounds were identified. The main components of the essential oil were borneoll (28.30%), 1,8-cCineole (20.98%), (-)-bBornyl acetate (6.65%), linalool (5.94%), (-)-.alpha.-terpinol (5.87%), caryophyllene oxlde (5.11%). The results indicates that Cinnamomum japonicum oil has a great potential to be developed into a ecofriendly mosquito repellent.