A method for manufacturing a field emission substrate is disclosed. The method includes the following steps: providing a substrate having a conductive layer; forming a hydrophobic layer on the conduction layer; patterning the hydrophobic layer; and removing the hydrophobic layer from the surface of the conductive layer so that the formed layer of electron-emitting materials can contact the surface of the conductive layer. The patterned hydrophobic layer can include plural bumps, and the pitches between the neighboring bumps are in a range of 1 .mu.m to 500 .mu.m. By way of the steps illustrated above, the emitting layer on the substrate can be made easily and arranged accurately. Hence, the electrons can be emitted homogeneously.