An electrostatic discharge protection structure comprises an isolation layer, a high voltage P-well, an N-well, a P-well, a first doped region of N-type conductivity, a second doped region of P-type conductivity, a third doped region of N-type conductivity, a fourth doped region of P-type conductivity, an anode, and a cathode. The isolation layer is disposed on a substrate. The high voltage P-well is disposed on the isolation layer. The N-well is disposed in the high voltage P-well. The P-well is disposed in the high voltage P-well, and the P-well is separated from the N-well. The first and the second doped regions are disposed in the N-well. The third and the fourth doped regions are disposed in the P-well. The anode is electrically connected to the first doped region and the second doped region, and the cathode is electrically connected to the fourth doped region.