Recently, 6 ASEAN countries including Indonesia, Malaysia, the Philippines, Singapore, Thailand and Brunei reached an agreement in Bali Island, Indonesia on intelligence cooperation, which aims to strengthen regional security multilateral cooperation, and resists the threats by reflux extremist organization--Islamic state--militants. Previously, the three countries of Indonesia, the Philippines and Malaysia had launched a joint maritime and air patrol. Some analysis points out that, with the collapsing of the 'Islamic State', the terrorist threat to Southeast Asia caused by the reflux extremists has multiplied. Southeast Asian countries should break the shackles of the existing anti-terrorism cooperation mechanism, and breakthrough the situation in which various countries combat terrorism alone so that their combat against terrorism can be more effective.