You can remove a layer from an image, or remove the contents of a layer. Removing a layer's contents will keep the layer within the image; raster and vector layers become transparent and the background layer is filled with the current background color and material.
To delete a layer:
Make sure nothing is selected outside the layer you wish to delete.
On the Layers palette, click the name of the layer you want to delete.
Delete the layer using one of these methods:
Choose Layers > Delete; or
Click the Delete Layer button 
on the Layers
palette toolbar ; or
Right-click to display the context menu, and then choose Delete; or
Drag the layer to the Delete Layer button and then release the mouse button.
To delete the contents of a layer:
Make sure nothing is selected outside the layer whose contents you wish to delete.
On the Layers palette, click the name of the layer.
Press the Delete key, or choose Edit > Clear.
Expanding and Contracting Layers and Layer Groups
Viewing the Contents of Layers
Arranging the Stacking Order of Layers
Moving Layers within the Image Canvas
Cleaning up the Edges of Layers Created from Selections