Due to limited resources and the threats to the security, a challenging problem is how to implement secure pairwise communications among any pair of sensors in a wireless sensor network. An Energy-based Key Management (EKM) scheme was proposed in this paper. This scheme stored identifier, residual energy and the pairwise keys into each node in the key predistribution phase, searched for better secure links according to the identifier and residual energy, and then took multiplied times hash functions to implement the security for EKM scheme the view of the multi-hop communication. Both analytical evaluations and extensive simulations of EKM scheme were provided. The results indicate that EKM scheme has lower energy consumption and longer the lifetime of the network, and reduces the probability of nodes capture.