is a vehicular ad hoc network. This is a part of mobile ad hoc network. VANETs also called as intelligent transportation system (ITS) in which vehicles convey to give auspicious data. Their point is to give security, information and management of network. Rather than of their numerous advantages vehicular network is inclined to various attacks. Like prankster attack, denial of service attack, black hole attack, alteration attack, fabrication attack, man in the middle attack, timing attack, illusion attack and so forth. In this research we will attempt to uproot Sybil attack in which node creates its multiple identities and it can be affected by various ways. In previous research researcher judge the estimated physical measurement on the bases of three parameter but it may also be the case that message delay occur due to various another reasons like queue problem, congestion problem, accidental problem, so this approach is not accurate due to absence of GPS. According to this work GPSR protocol will be used through which physical measurement of vehicle can be verified at any time and GPS coordinates will be compared. If GPS coordinate matched then there is no attack. KeywordsVanet's, WSN, GPSR, GPS