The present invention provides a multi-round questioning and answering method, a method for generating a multi-round questioning and answering system and a method for modifying a multi-round questioning and answering system. The multi-round questioning and answering method includes: acquisition initial request information, and matching the initial request information with a knowledge point in a knowledge base; if it is determined that the initial request information matches with a thematic question in a thematic knowledge point, triggering a root node of a multi-round questioning and answering flow module corresponding to the thematic knowledge point; and, performing, according to a first interaction node to which the multi-round questioning and answering flow module is proceeded currently, one or more knowledge points corresponding to the first interaction node stored in the knowledge base and user interaction information input by an interactive user, questioning and answering interaction with the interactive user.