A quick assembly and quick disassembly device for a faucet, configured for fastening of the faucet, comprises a base seat, an upper cover, and at least two locking blocks. The base seat comprises a mounting hole. The upper cover is sleeved outside of the faucet and is detachably connected to the base seat. Each of the at least two locking blocks comprises a first inclined surface pushed by at least two transmission members to enable the at least two locking blocks to move radially inward to abut the faucet. A position-providing notch between two adjacent locking blocks provides a space for a joint of a flexible hose so as to easily mount or detach the faucet. A distal end of the at least two elastic assemblies is disposed in at least two locking blocks to enable the at least two locking blocks to move outward to release the faucet.