Method and system for avoiding digital synchronization network clock ring formation and terminal

The present invention discloses a method and a system for avoiding digital synchronization network clock ring formation and a terminal. The method comprises the steps of: receiving a clock identifierwith a clock source ID type sent by an adjacent network element or a clock identifier with an MAC address type having a corresponding relation with the clock source ID from a corresponding circuit through each circuit clock source; for each circuit clock source, determining whether the circuit clock source is available or not according to the received clock identifier; according to the received clock identifier type, determining the clock source ID transmitted by the adjacent network element, comparing whether the clock source ID is consistent with all the clock source IDs or not to determinewhether the circuit clock sources are available or not; selecting one clock source from the available clock sources as a current used clock source; and controlling each circuit clock source to send the clock identifier, the clock quality grade and the clock of the current used clock source to the adjacent network element through the corresponding circuit. The method and the system for avoiding digital synchronization network clock ring formation and the terminal can flexibly avoid clock ring formation.