In sensor network where large group of nodes share the information, in such scenario it’s difficult to scale the application, in addition security in wireless sensor network often vary with purpose and context, but in broad-spectrum, security for wireless sensor networks should centered on the protection of the data itself and the network communications between the nodes. Privacy, reliability and validation are the most important data security concerns. Traditional cryptographic methods are not promising on resource limited sensor nodes. Node initiated key management is a novel idea where rather than base station or key distribution center initiate the security algorithm. We can give control to sensor nodes or cluster head for securing communicating nodes with in a sensor network. It is a non centralized key management method which is more robust than other methods. in this paper we proposed the proactive key management which guarantee efficiency, robustness, and dynamic clustering.