Since 1990s, despite the strong opposition of the international community, North Korea has frequently conducted nuclear weapons tests and missile tests, and the DPRK nuclear issue has become an important factor affecting the security and stability of the Asia-Pacific region. As an extremely important multilateral organization in the Asia-Pacific region, ASEAN has gradually increased its influence in the Asia-Pacific region with the advancement of integration in recent years. In order to further enhance its influence and enhance its participation in Asia-Pacific affairs, ASEAN has been trying to give its voice on the Korean nuclear issue. The ASEAN Regional Forum and ASEAN Summit are the most important platforms for ASEAN to express its position and views. Since the North Korean nuclear issue became prominent, the North Korean nuclear issue has been a key topic discussed in the ASEAN Regional Forum and ASEAN Summit. Judging from the conference documents produced by the conferences over the years, ASEAN's attitude towards the Korean nuclear issue is still being fine-tuned. Although the international community has repeatedly issued policies to condemn North Korea and impose economic sanctions, ASEAN is generally neutral and conservative in its attitude towards the DPRK nuclear issue, and it is also very cautious in its actions. Recently, with China and Russia following the United States, they began to impose severe economic sanctions on North Korea, and their words changed to severe condemnation, and ASEAN's attitude towards North Korea also changed subtly. To some extent, the changes of the Korean nuclear issue in ASEAN reflect the constant fine-tuning of ASEAN's foreign policy. This paper aims to find out the fine-tuning of ASEAN's foreign policy and its influence on ASEAN by combing the changes of ASEAN's Korean nuclear issue and the potential reasons behind the changes.