Provided are a data sending method and device in spectrum aggregation. When downlink aggregation is performed on the plurality of cells of different types, the method includes that: HARQ information of the plurality of cells is centralized and sent on uplink subframes corresponding to a TDD cell among the plurality of cells, wherein the TDD cell is a primary cell while other cells are secondary cells and it is given that an uplink-downlink configuration of the primary cell is configuration X, where X∈{0,1,2,3,4,5,6}, downlink subframes are configured on each FDD cell for a UE so that a network can send a PDCCH/a PDSCH for the UE only on the configured downlink subframes while the UE detects and receives the PDCCH/PDSCH on the configured downlink subframes.