A method and device for detecting whether a missed call is valid are disclosed in the present invention. Wherein, the method for detecting whether a missed call is valid includes the following steps: when a call is not successfully established, a network side prompting a caller to enter authentication information and sending the authentication information entered by the caller to a called terminal side in a form of a short message; the called terminal side receiving and identifying an authentication short message, judging whether the authentication short message is valid, and authenticating the corresponding incoming call number to be authenticated in a cache by using the authentication information when the authentication short message is judged to be valid; and the called terminal side writing the incoming call number passing the authentication into a missed call record.