The adduct of photoproduct of anhydromethylberberine with dimethyl acetylene-dicarboxylate has been investigated by means of the nuclear magnetic resonance spectroscopyand the nuclear Overhauser effect measurements to establish the structure, in which the B/C ring juncture is cis and the conformation of B ring is a flattened boat form. Theselective reduction of adduct with lithium aluminum hydride and the reduction of adduct with hydrazine in the presence of oxygen are studied.