The present invention discloses a child node, a parent node, and a caching method and system for a multi-layer video network. The multi-layer video network includes at least one parent node and multiple child nodes connected to the parent node. The method includes: collecting a user request arrival rate of each child node with respect to each content in a content set; and determining an optimal storage policy and an optimal upload bandwidth allocation policy of each child node with respect to each content based on the user request arrival rate, storage capacity and upload bandwidth of each child node, and a size of each content. According to the content disclosed above, the technical solution disclosed by the present invention can save network bandwidth as much as possible and implement coordination among cache nodes, and is compatible with a heterogeneous network resource environment.