A root node selection system includes a plurality of idle nodes, and each idle node has a signal quality parameter. The each idle node is configured to broadcast a signal beacon and monitor other signal beacons, where each signal beacon carries the corresponding signal quality parameter. Any of the idle nodes is used as a to-be-selected node, and the to-be-selected node stores a signal quality table. The signal quality table includes a signal item and a rank item. The signal item includes the signal quality parameters. The rank item includes a plurality of ranks, and the ranks correspond to the signal quality parameters in the signal item in a one-to-one manner. The to-be-selected node serves as a root node of a mesh network based on that the rank corresponding to the signal quality parameter of the to-be-selected node is greater than a rank threshold.