The invention discloses a method for implementing Calling Tapping at Flash, which includes the steps of: when there is a new voice message for a user, actively initiating an SIP message carrying the description information of the voice message by a Voice Mail Application Server; sending the SIP message to the user terminal or the home network device of the user by the Voice Mail Application Server, and notifying the user by the user terminal or the network device; converting the SIP message into an inter-exchange signaling message in CS domain and transmitting it to the CS domain where the user accesses by a Media Gateway Control Unit (MGCU), and notifying the user by a switching control unit in the CS domain in accordance with the prompt means of Calling Tapping at Flash of the user. The invention also discloses a communication system for implementing Calling Tapping at Flash service.