This application related to method and apparatus for aggregation of frequency division duplex and time division duplex. One embodiment of method comprises receiving signals from a cell configured with FDD and/or a cell configured with TDD according to the downlink scheduling, adjusting timing of uplink transmissions for the cells configured with FDD or the cell configured with TDD when the UE detects timing difference between the cells, and transmitting uplink signal to the cell configured and/or a cell configured with TDD based on the adjusted timing.