A method of providing a voice mailbox function in a PoC service, including: if the voice mailbox of at least one called user is to be connected in response to receiving a session establishment request from a calling user, determining whether the session corresponding to the session establishment request is a one-to-many session; and recording a message from the calling user through the voice mailbox if the session is a one-to-many session. The invention further discloses a method in a PoC service of notifying of a message in a voice mailbox, and a PoC service server.