A light emitting device, a manufacturing method thereof and a display device are disclosed. The light emitting device includes a light-emitting unit, a structured light guide layer, a light guide unit and a patterned reflective layer. The light-emitting unit has a circuit substrate and multiple light emitting elements, and the light emitting elements are separately disposed on a surface of the circuit substrate. The structured light guide layer is disposed opposite the light-emitting unit, and has multiple accommodating slots and multiple light guide structures disposed between the two accommodating slots. Each accommodating slot is disposed in correspondence with each light emitting element, and the light guide structures are disposed on the bottom surface of the structured light guide layer. The light guide unit is disposed on the top surface of the structured light guide layer. The patterned reflective layer has multiple reflective patterns disposed on the light emitting surface of the light guide unit, and each reflective pattern is disposed in correspondence with each light emitting element.