Skyline query has been applied widely in sensor networks. We propose a connected key node setbased skyline Efficient skyline query processing(EffiSky)algorithm to minimize communication traffic for resourceslimited sensor networks. In the EffiSky algorithm, we discover a Connected key node set(CKNS) used to transmit and collect queries and results among the sensor nodes, which can reduce the average communication cost of the networks significantly. We set up a two-level filtering scheme that prunes many useless dominated tuples. Both the theoretical analysis and experiment results demonstrate that EffiSky excels the existing work in terms of network traffic, scalability in network expansion, node density, and dimension change. Skyline query has been applied widely in sensor networks. We propose a connected key node setbased skyline Efficient skyline query processing (EffiSky) algorithm to minimize communication traffic for resources limited sensor networks. In the EffiSky algorithm, we discover a Connected Key Node Set (CKNS) used to transmit and collect queries and results among the sensor nodes, which can reduce the average communication cost of the networks significantly. We set up a two-level filtering scheme that prunes many useless dominated tuples. Both the theoretical analysis and experiment results demonstrate that EffiSky excels the existing work in terms of network traffic, scalability in network expansion, node density, and dimension change.