Wireless ad-hoc sensor network is prominent platform for communication and research. Wireless adhoc sensor network is vulnerable to Denial of Service (DOS) attack. Denial of service attack(DOS) makes resources are blocked and not available to users. This Denial of service attack is create suitable condition for Vampire attack and make main cause for it. In Vampire attack it makes the node to consume more battery power and degrades the network performance. Vampire attack does not rely on any particular type of routing protocol. In propose system energy consumption and trust value is calculated for each node to mitigate the vampire attack.