A device for enhanced oil-water separation and desalination comprising: - a casing, an oil-water-gas inlet located on the casing, - an water injection port and a T-shaped liquid-gas separator, which is a rotational flow degasser, wherein the water injection port and the T-shaped liquid-gas separator are separately connected with the oil-water-gas inlet and the water injection port is located before the T-shaped liquid-gas separator; - a second injector comprising a water injection port, a flow rectification distributor, a hydrophilic droplet agglomeration module comprising baffle plates, a corrugated plate interceptor fast separation module, an oil-water interface level controller, a partition, a deep water removal module which is a conjugated fiber water removal module containing hydrophilic fibers and oleophilic fibers, a liquid level controller, which are disposed within the casing in said order, wherein the amount of the hydrophilic fibers is 5 to 15% of that of the oleophilic fibers in the conjugated fiber water removal module; - a deep oil removal module, which is a conjugated fiber oil removal module containing hydrophilic fibers and oleophilic fibers, located on the bottom of the casing and a gas outlet at the top of the casing, wherein the amount of the oleophilic fibers is 10 to 20% of that of the hydrophilic fibers in the conjugated fiber oil removal module and an oil-water interface level controller is located below the deep oil removal module and wherein the oil removal module is positioned at a height lower than the deep water removal module; and - an oil outlet located on the posterior part of the casing, a water outlet located on the bottom of the casing and a water outlet located below the oil-water interface level controller, wherein the water outlet is located before the partition and both of the water outlets are led to a water mixture outlet, and wherein regulating valves (11-1, 11-2 and 11-3) are provided on the oil outlet, the water outlet and the water outlet respectively and the regulating valves (11-1, 11-2 and 11-3) are controlled by the level controllers (10, 13-1 and 13-2) respectively. - a casing, an oil-water-gas inlet located on the casing, - an water injection port and a T-shaped liquid-gas separator, which is a rotational flow degasser, wherein the water injection port and the T-shaped liquid-gas separator are separately connected with the oil-water-gas inlet and the water injection port is located before the T-shaped liquid-gas separator; - a second injector comprising a water injection port, a flow rectification distributor, a hydrophilic droplet agglomeration module comprising baffle plates, a corrugated plate interceptor fast separation module, an oil-water interface level controller, a partition, a deep water removal module which is a conjugated fiber water removal module containing hydrophilic fibers and oleophilic fibers, a liquid level controller, which are disposed within the casing in said order, wherein the amount of the hydrophilic fibers is 5 to 15% of that of the oleophilic fibers in the conjugated fiber water removal module; - a deep oil removal module, which is a conjugated fiber oil removal module containing hydrophilic fibers and oleophilic fibers, located on the bottom of the casing and a gas outlet at the top of the casing, wherein the amount of the oleophilic fibers is 10 to 20% of that of the hydrophilic fibers in the conjugated fiber oil removal module and an oil-water interface level controller is located below the deep oil removal module and wherein the oil removal module is positioned at a height lower than the deep water removal module; and - an oil outlet located on the posterior part of the casing, a water outlet located on the bottom of the casing and a water outlet located below the oil-water interface level controller, wherein the water outlet is located before the partition and both of the water outlets are led to a water mixture outlet, and wherein regulating valves (11-1, 11-2 and 11-3) are provided on the oil outlet, the water outlet and the water outlet respectively and the regulating valves (11-1, 11-2 and 11-3) are controlled by the level controllers (10, 13-1 and 13-2) respectively.