Due to the mobility and non-centralized management, Mobile adhoc Network (MANET) is broadly used in current communication system. The researchers have been proposed various MANET routing protocols in order to improve network reliability. However, most of the MANET routing protocols have lack of attack prevention. While the MANET communication system becomes larger, the various types of attacks appear in parallel. Therefore, performance analysis of attacks in routing protocols is one of the important issues in the case of MANET improvement. In this paper, two routing protocols, AODV and DSDV were tested with black hole attack. The performances of those two protocols were compared when they were attacked by malicious node.