Japan wants to participate in global politics through climate reduction and attaches great importance to the security issues brought about by climate change. Climate change has increased extreme weather in Japan， and led to the deterioration of its coastal ecological environment and the decline in the quality of agricultural products， which has brought the resource?poor island nation more challenges， further affecting Japan's homeland security. Japan has actively carried out climate diplomacy in Asia， strengthened its diplomatic relations with countries in the region to maintain the "US?Japan Alliance" in climate strategy， and to coordinate American "Indo?Pacific Strategy" with climate diplomacy. However， Japan's discharging nuclear sewage into the sea has seriously broken down its international image. By changing the concept of energy security， Japan has endeavored to developing and promoting emission reduction technologies， and to responding to the impact of climate change on its economic security with technological advantages. In view of Japan's experience， China should strike a balance between climate change and national security from the perspective of overall national security， and coordinately promote his climate emission reduction policies.