The present invention provides an optical conversion structure and a display device. The optical conversion structure includes a base layer, a middle layer, and an optical conversion layer. The base layer has a first refractivity, the middle layer has a second refractivity, and the optical conversion layer has a third refractivity. The optical conversion layer includes a first optical conversion unit, a second optical conversion unit, and a third optical conversion unit. The first optical conversion unit, the second optical conversion unit, and the third optical conversion unit have different light colors. The second refractivity is greater than the first refractivity and the third refractivity.