Abstract: This paper presents an approach based on attack utility to recognize the attacker′s finally intention and forecast the next possible attack. This paper describes a multi-attack by the attack intent, and establishes the multi-attack the logic diagram based on the attack intention. During the procedure of the attack forecast, attack utility is used to represent the attackers benefit for each attack step. The attack utility is an important reference for the multis-step attack forecast. At the end, the validity of the algorithm is proved by the experimental results.