The invention discloses a dense-dilute separation type cross-load decoupling combustor. The combustor comprises a central air duct, an inner primary air duct, a dilute side inner primary air collecting channel, an inner primary air dilute side leading-out pipe, a swirl inner secondary air duct, an outer primary air duct and a swirl outer secondary air duct, pulverized coal dense-dilute separatorsarranged on the inner wall of the inner primary air duct are in a necking shape along the airflow direction, the surfaces of the pulverized coal dense/dilute separators are three-dimensional filter powder holes or three-dimensional filter powder gaps which are arranged in a staggered mode, the dense-dilute separation effect is enhanced, the dilute side inner primary air collecting channel which isarranged behind the pulverized coal dense-dilute separators is communicated with the inner primary air dilute side leading-out pipe and is communicated with the outer primary air duct, the dilute side inner primary air collecting channel is used for supplying air for the outer primary air duct during low-load operation of the boiler. The combustor can realize coupling and decoupling operation ofthe inner primary air and the outer primary air during variable load operation of the boiler, the dense-dilute separation is realized, the combustion stability is improved, the NOx emission is reduced, and the overall energy consumption of the boiler is reduced.