The present invention relates to a robust coverage method for relay nodes in a double-layer structure wireless sensor network. The present invention is a local search based relay node 2-coverage deployment algorithm which, by means of reducing the global deployment problem to a local deployment problem, achieves optimal deployment while ensuring robustness. The method specifically comprises two steps: first 1-coverage and second 1-coverage, wherein the first 1-coverage comprises the three steps of construction of relay node candidate deployment locations, grouping of sensor nodes and local deployment of relay nodes, wherein the sensor nodes are grouped by means of a novel grouping method, and the complexity of the algorithm is reduced while ensuring optimal deployment. The second 1-coverage adjusts a threshold, selects from every group the sensor nodes covered by just one relay node, and uses a 1-coverage method to re-implement 1-coverage of the sensor nodes, thereby ensuring robustness, reducing the number of relay nodes deployed, and shortening the problem-saving time.