The present disclosure provides an item recommendation method and system based on a user intention in a conversation session. In this method, a current conversation session is encoded by use of items of prior time sequence and the last item so as to generate an accurate conversation session representation which is then used to perform initial item prediction as a user intention. Afterwards, an intention-guided neighbor detector is used to locate an accurate neighbor conversation session. Finally, the current conversation session and the neighbor conversation session representations are combined adaptively by a gated mixed layer to generate the final item recommendation, so as to effectively improve the accuracy of item recommendation.