A method for multiuser superposition transmission (MUST) in a wireless communication system, and a device therefor are disclosed. Particularly, a method by which a first base station (eNodeB (eNB)) performs MUST involving joint transmission in a wireless communication system can comprise the steps of: receiving, from a MUST-paired near user equipment (UE), first channel state information (CSI) for the first eNB participating in the joint transmission; setting a parameter required to perform the MUST involving the joint transmission for the MUST-paired UE, on the basis of the first CSI and the second CSI for a second eNB participating in the joint transmission; and transmitting the parameter to the MUST-paired UE and the second eNB.