Abstract: This paper mainly compares and researches three significant routing protocols for Ad-Hoc network i. e. DSDV, DSR and AODV. It analyzes these protocols in terms of Ad-Hoc packet loss rate, routing consumption, end-to-end delay, packet delivery ratio through simulations performed in Network Simulator(NS-2) for varying network conditions like the number of nodes, maximum speed of mobile host and the sending frequency of data source. Finally, it draws the performance differences of three protocols, and sums up the scenarios for which they are best suited.