The invention relates to an input device with locking function and the locking method thereof. And the input device is connected to a computer system and comprises a connection interface, a pressure sensor and a microcontroller, where the connection interface is used to connect the input device to the computer system; the pressure sensor is used to generate pressure sensing signal by the receivedpressure when the input device is normally arranged; the microcontroller real-timely scans the pressure sensing signal, and generates a locking signal to the computer system when not finding the pressure sensing signal to force the computer system to execute system locking, so as to make others unable to operate the computer system and thus achieve the purpose of protecting the data in the computer system.