The present invention discloses a remote radio unit and a base station system. The remote radio unit includes an active part and a passive part, where the active part and the passive part are placed respectively on an active module and a passive module that are independent of each other and the active module and the passive module are connected via a pluggable connecting device. Because the passive part is more reliable and less liable to breakdown than the active part, when the active part needs to be repaired, it is unnecessary to dismantle the entire unit. Therefore, the repair is easier and faster and the repair cost is lower. The operation reliability of the base station system is also improved.