An over-voltage protection apparatus includes an input voltage detection module (12) and a second switch (14). The input voltage detection module (12) includes a switch assembly (121), a rectifying circuit (122), a voltage detection circuit (123), and a voltage protection circuit (124). The rectifying circuit (122) rectifies an AC power source (Vac) to generate a DC voltage (Vb). The voltage protection circuit (124) controls the second switch (14) to disconnect the AC power source (Vac) to supply a load (90) when the voltage detection circuit (123) detects that the DC voltage (Vb) reaches to a first over voltage value (Voth1). The voltage protection circuit (124) controls the switch assembly (121), thereby providing a voltage-limiting protection and a current-limiting protection when the voltage detection circuit (123) detects that the DC voltage (Vb) reaches to a second over voltage value (Voth2).