Provided are a method and a device for timing a scheduled charging, and a terminal device. The method for timing a scheduled charging comprises steps of: acquiring, in response to a condition that a charging gun is connected, a scheduled-charging start time for equipment and a first current-absolute-time at which a connection of the charging gun is completed; determining a first time duration to the scheduled-charging start time according to the scheduled-charging start time and the first current-absolute-time; performing a compensation on the first time duration to obtain a second time duration, and starting a timing; and terminating the timing, when the second time duration is reached, and waking up the equipment.