An electrostatic protection circuit includes a strained transistor array, an unstrained transistor, and a control circuit. The strained transistor array has a first end electrically connected to a bias terminal. The unstrained transistor has a first end electrically connected to the bias terminal. The control circuit is electrically connected to a second end of the strained transistor array, a second end of the unstrained transistor and a ground terminal. The control circuit controls impedance between the second end of the strained transistor array and the ground terminal according to current flowing through the unstrained transistor. The electrostatic protection circuit is capable of preventing latch-up effect.