In order to prevent MANET from wormhole attack, a new method is proposed. In this, wormhole attack in MANET is detected and prevented by using Hop Count, Reverse Trip Time and Link Length method. According to the scheme, hop count specifies the actual reverse trip time from source to destination. To find the presence of tunnel, the source will compare calculated reverse trip time with actual reverse trip time and to verify the presence of tunnel, the source will compare calculated link length with actual link length of the links in paths. This scheme provides a security to mobile ad hoc networks from both short as well as long wormhole tunnels. Network simulator is used to evaluate the performance of mobile ad hoc network. The simulation results show that the proposed scheme outperformed in terms of throughput and packet delivery ratio.