A method for accessing to a mobile communication network, comprising: acquiring a session matching level for each cell, which is calculated based on a session type of a session initiated by a user terminal as needed, a session data rate available to the user terminal of each cell and load balance parameters of each cell; accessing to a cell selected according to the session matching level for each cell. Further, it also provides another method for accessing to a mobile communication network, and corresponding user terminal, network-side device and communication system.