Cyber attack nowadays is increasingly being reported. Defenders need a good understanding of attacker’s perspective in order to accurately anticipate threats and effectively mitigate attacks. This understanding can be obtained through sharing attack pattern. However, in the existing researches the consideration about information sharing is not integrated into the attack pattern concept. In this paper, we propose an attack pattern ontology as a common language of information sharing; the goal is to demonstrate how this ontology may effectively support cyber security information sharing. Based on the existing theories about attack pattern, we developed an ontological model to present attack information. The research can be further developed to integrate attacker profile ontology with the attack pattern ontology, which enables more systematic analysis of cyber attacks.