The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for performing SCG re-establishment in dual connectivity in wireless communication system, the method comprising: detecting radio link failure on a secondary node, wherein the UE is configured with a master node and the secondary node; and receiving signals from candidates of a new secondary node for obtaining information about which cell is a best candidate on the new secondary node to prepare for radio link failure on the secondary node; and initiating RRC connection re-establishment procedure for recovery from the radio link failure of the secondary node if a cell which is to be a PSCell on a new secondary node is selected in a cell list.