A three-way handshaking method includes: controlling a first port in a first specific mode to send a first specific signal to a second port, and controlling the first port to enter a second specific mode; when the first port receives a second specific signal, determining the second port is in the second specific mode and controlling the first port to send a third specific signal to the second port; and when it is determined that the second port is in a third specific mode, controlling the first port to enter the third specific mode.