Provided is a cross-domain parallel recovering method and system in multi-layer and multi-domain distributed optical network (MMDON). Based on inter-domain LRA (Link Recovery Algorithm), the routing devices establish inter-domain WP (Work Path) and then build inter-domain RP (Recovery Path) based on WP. Inter-domain RPs will be established by using PSM (Parallel Signaling Mechanism) when link failure occurs on inter-domain WPs. That realizes the establishments and of inter-domain RP, and improves the survivability of inter-domain services. Inter-domain RPs are established or engaged before the establishing of WPs, while the intra-domain paths are established after the failure testing. This mechanism ensures the availability of inter-domain resources during recovery and avoids resource waste caused by pre-establishing intra-domain RPs. Moreover, parallel signaling mechanism can decrease the recovery time, and can handle inter-domain link failures simultaneously to avoid queue-waiting.