Researcher have made vital and significant out comes in the field of Body Sensor Network (BSN) due to its central role in health monitoring system form last decade. Due to thin-skinned character of its data it desires to maintain confidential and magnify security challenge. Key association proposals have unusual interested in BSN because of small tiny nature and daily life usage of these electronic devices. The key role in safe and sound communication is key management practices. Confidentiality, authentication and integrity are achieved by applying key agreement and management methods. Accomplishment of key agreement in BSNs is very daunting task. In this paper we have presented a hybrid novel approach with rekeying for BSNs. Our scheme is based on symmetric and Elliptic curve cryptography. The existing key agreement schemes have lack of; security strength, scalability and some schemes take high computation cost and communication overhead. If only symmetric key scheme apply then scalability and security problems occur. And if only public key scheme apply then computation cost and key storage memory issues occur. Our proposed key agreement model is based on Elliptic curve and symmetric cryptography. We testify our results using NS 2.35. The proposed scheme reduces twenty seven to seventy four percent memory requirements for keys storage, fifty to eight four percent computation cost and twenty to sixty one percent communications overhead and also provides rekeying features.