A display panel, a manufacturing method thereof and a display device are provided. The display panel includes a base substrate, a pixel definition layer, a light emitting layer and a spacer. The pixel definition layer is configured to define each of subpixels in the display panel and includes a groove structure which is disposed between adjacent subpixels, the spacer is disposed in the groove structure, the light emitting layer is disposed on a side of the pixel definition layer and the spacer away from the base substrate, and a thermal expansion efficient of the spacer is greater than a thermal expansion efficient of the light emitting layer.