This book contains the authors’ research results on energy-efficient routing technologies in wireless sensor network, and its main content includes the following: a clustering heterogeneous network routing algorithm based on mixed integer programming; an adaptive aggregation routing algorithm with the minimal energy expends in wireless sensor networks on the premise of considering both aggregation cost and communication cost; the lowest energy consumption routing algorithm, the energy balancing and lowest energy-consumption routing algorithm, and the least delay and low energy-consumption routing algorithm on the basis of dynamic programming method.