Time synchronization method based on double ring bus

The invention relates to a time synchronization method based on a double ring bus; the method comprises the following steps: initializes master/slave equipment; the master equipment packages a sending time to synchronization messages sent to the adjacent slave equipment; the slave equipment i stores a synchronization message, coming from a loop, receiving time ti and packages a synchronization message sending time ti' into the synchronization message sent to the slave equipment i+1, and the slave equipment i+1 stores a synchronization message receiving time ti+1; simultaneously in another loop, the slave equipment i+1 sends another synchronization message, going to the slave equipment i, sending time si+1 and the time ti+1 to the slave equipment i through the synchronization message; the slave equipment i saves the message receiving time si; the slave equipment i calculates a clock deviation amount and communication delay between the slave equipment i and the slave equipment i+1, and corrects a local clock, thereby completing time synchronization of the double ring bus master/slave equipment. The synchronization message can be simultaneously sent a transmission line, and the synchronization can be completed in one communication period, thereby effectively improving instantaneity; and synchronization efficiency is high.