The invention discloses a method and apparatus for judging switch non-full-phase opening. The method comprises the steps of collecting real-time operation data of a grid switchgear, wherein the real-time operation data comprises position change information of the switchgear; if the position change information of the switchgear is received as an open position, determining whether the switch open position operation is a remote control operation for scheduling an automation main station; if the switch open position operation is determined to be a non-remote-control operating for scheduling the automation main station, recording the type and the opening time of the switchgear as the opening information of the switchgear and recording the opening information into an opening queue; and if the opening time of the switchgear continues to a predetermined threshold, starting switch non-full-phase opening judging; if it is determined that the current switchgear is in non-full-phase opening, generating a non-full-phase opening brief report of the current switchgear, giving an alarm and carrying out display. The invention also discloses an apparatus for judging switch non-full-phase opening to realize the above method. The method and apparatus of the invention effectively puts an end to electric power accidents due to loaded disconnecting link pulling in the switch non-full-phase opening.