A method and system for service protection based on the Dual Node Interconnection (DNI) protection structure in the transport network are provided. When creating a DNI protection group, a plurality of services are configured in one direction, wherein one is a working service, and the others are protection services; the multiple services have the same add node and drop node, but not exactly the same passed interconnection nodes; on each interconnection node of the add ring, two services in the DNI protection group through the local node to the drop ring are adapted as two services in a 1+1 protection group; on the drop node, services in the DNI protection group are adapted as two services in a 1+1 protection group transmitted from two directions of the drop ring; when a fault occurs, said interconnection node and drop node execute switching according to the 1+1 protection protocol.