A method, an apparatus, and a system for cross-platform conference convergence are disclosed in embodiments of the present invention, where implementation of the method includes: receiving, after attending a first conference, an INVITE request sent by a first application server, where the INVITE request is a request for inviting a second terminal served by a second application server to attend a first conference; sending an invitation call to the second application server to request creating a second conference; and sending, after receiving conference creation success information sent by the second application server, an invitation to the second application server to invite the second terminal to attend the second conference. Usage of a private line between an enterprise and an operator can be eliminated in the entire implementation process.