To make efficient use of limited energy resources is significant in WSNs

a major way to save limited energy resources is constructing a smaller virtual backbone

which is equivalent to find the minimum connected dominating set（ MCDS） in graph theory. Thus

a heuristic algorithm to construct the MCDS is proposed. Firstly

according to average formula

establish ordered list for vertex

then construct the maximum independent set（ MIS）

and then connect nodes of MIS

finally

optimize CDS. Simulation experiments show that the algorithm can find smaller connected dominating set in short time

and effectively balances energy of each node to extend lifetime of network.