The invention discloses a hydroxyl-containing half-sandwich rutheniumcoordination compound, a preparation method and a method for reducing nitrobenzene compounds into aniline compounds. A structure of the hydroxyl-containing half-sandwich rutheniumcoordination compound is as shown by formula (I), where X is halogen and R is H, hydrocarbonyl of C1 to C6 or halogen. By adopting the method, the high-yield half-sandwich rutheniumcoordination compound can be prepared under mild conditions, and the half-sandwich rutheniumcoordination compound can reduce nitrobenzene compounds into aniline compounds under mild conditions.