A transmission line with rotatable connector includes an insulated body, a connector a transmission line and a rotatable assembly kit. The insulated body includes a storage space. One end of the insulated body includes an opening slot and the other end of the insulating body includes a sliding slot. The connector is inside of the storage space. One end of the connector protrudes from the opening slot. One end of the transmission line is embedded in the storage space and electronically connected with the connector. The other end of the transmission line protrudes from the insulated body. The rotatable assembly kit includes a rotatable cylinder and a wire cover extending from one side of the rotatable cylinder. The rotatable cylinder is rotatably and pivotally connected to the rear of the connector. The partial transmission line protruding from the insulated body is covered by the wire cover and the partial transmission line horizontally moves along the sliding slot accompany with the rotation of the rotatable cylinder. The transmission line can properly change the direction of the connector to make it convenient for use and also can avoid the breakup of the junction of the transmission line at the bending point.