3-Cyanomethyl oxoindoles are a kind of important drug intermediates, which can be used to synthesize horsfiline, esermethole and physostigmine and other natural products via the conversion of cyano functional groups. A domino Heck/cyanation reaction in aqueous was developed to afford 3-cyanomethyl oxoindole compounds. This method, using green medium water instead of organic solvents, without any basic additives, provided a green and efficient new procedure for the synthesis of 3-cyanomethyl oxoindoles.