The invention discloses a missing semantic supplementing method for a multi-round question-answering system. The missing semantic supplementing method is characterized by comprising the following steps of S1, obtaining questions input in the question-answering system by a user; S2, performing missing semantic supplementation for the current questions according to previous questions input by the user, wherein the missing semantic supplementation refers to semantic supplementation from the point of anaphora resolution and/or omission and recovery; and S3, performing searching on the current questions after the missing semantic supplementation is completed. According to the missing semantic supplementing method, the missing semantic supplementation for the current questions is carried out through the anaphora resolution and/or omission and recovery; accurate answers for the questions input by the user can be obtained; and the method allows the user to ask questions by using elliptical sentences, so that the fluency and accuracy of the man-machine interaction are improved, and a better user experience is achieved.