Abstract: Seven alkaloids have been isolated from the over ground parts of Cyclea hainanensis Merr (Menispermaceae) grown in Hainan is]and. Six of them are identified to be (-) curine (Ⅰ), (+)-4"-O-methylcurine (Ⅱ), hayatine (Ⅲ), d-isochondodendrine (Ⅳ), α-cyclanoline (Ⅴ), and a new quaternary alkaloid named α-hainanine (Ⅵ) respectively. Alkaloid (Ⅶ) is being identified. Dimethiodide and Dimethochloride derivatives of alkaloids (Ⅰ)—(Ⅲ) show neuromuscular blocking activity, but disochondodendrine hydrochloride possesses distinct analgesia.