Disclosed are a device-to-device (D2D) data transmission method of a user equipment (UE) in a wireless communication system and a UE using the method. The method comprises: receiving multiple resource pools and a resource pool configuration for configuring priority order information on each resource pool; and selecting a particular resource pool to transmit D2D data among the multiple resource pools on the basis of the priority order information on each resource pool, wherein the priority order information on each resource pool indicates the priority order of D2D data capable of using each of the multiple resource pools.