The advanced metering infrastructure(AMI)is a key component part of the smart grid

and wireless sensor networks(WSNs)are playing an increasingly important role in AMI. Cyber security is the prerequisite to ensure reliable operation of AMI. To guarantee communication security of WSNs in AMI

this paper proposes a key management scheme based on the elliptic curve cryptography(ECC). According to the ways of information transmission in AMI

the scheme is categorized as key management processes of unicast communication and multicast communication. In the scheme

the selection of elliptic curve

the calculation of ECC public and private keys in each sensor node

and the establishment

distribution and update of the keys in unicast communication and multicast communication are elaborated. The analysis results show that the proposed key management scheme is secure

and consumes less memory and energy. Thus the demands of AMI on communication security can be satisfied. This work is supported by National Natural Science Foundation of China(No. 51077015)and Fundamental Research Funds for the Central Universities(No. HIT.NSRIF.2015017).