Embodiments of the present invention relate to the technical field of wireless communications, and more particularly to a buffer state reporting method, system, and device, so as to perform buffer state reporting regarding an inter-eNB aggregation scenario. A buffer state reporting method provided by an embodiment of the present invention comprises: a user equipment, that aggregates resources of multiple network side devices, determining buffer state information; the user equipment reporting the buffer state information to at least one network side device participating in the aggregation, so as to realize buffer state reporting regarding the inter-eNB aggregation scenario, and enable multiple eNBs to obtain the buffer state information in the case of inter-eNB aggregation, thereby realizing resource scheduling.