Various embodiments may relate to a fault detection device for streetlamp lighting system. The streetlamp lighting system includes multiple load groups which are powered by a power cable. The fault detection device includes a master detection control unit and load detection control units configured for respective load groups, wherein the master detection control unit determines, according to a first fault feedback signal provided by respective load detection control unit, whether the load group corresponding to the load detection control unit is failed, while the streetlamp lighting system is in a first state, and the master detection control unit determines, according to a physical quantity detected on the power cable, whether the power cable is failed, while the streetlamp lighting system is in a second state. In addition, various embodiments further relate to a method of controlling the fault detection device.