In recent years，Japan’s security strategy has implemented major adjustments and substantive transformation，which can be expressed as a shift from “conservative defense” to “moderate offense.” The main measures of Japan’s security strategic transformation are as follows：by increasing the defense budget year after year，carrying out the reform and reorganization of the defense system and mechanism，gradually expanding the defense space to the fields such as the universe，space and network. Through comprehensively strengthening the Japan US alliance，vigorously supporting the four side security to the telephone system，and increasingly expanding the scope of multilateral allies，Japan aims to improve the national security level as a whole. The significant adjustment of Japan’s security strategy will inevitably bring unprecedented negative impact on the geopolitical environment of East Asia，and it will also pose a huge challenge that can not be underestimated to the security environment of neighboring countries.