Iran，one of the earliest countries to apply for membership in the SCO，signed a memorandum on the obligations of the Islamic Republic of Iran to join the SCO during the Samarkand Summit on September 16，2022. This marks Iran’s imminent accession as a full member of the SCO. Iran’s accession to the SCO is a profound result of the evolution of the international/regional order. It is also an inevitable response by China，Russia，and Iran to the constantly changing global and regional situation. In the evolution of democratisation of international relations and multi-polarization of the international order，the main driving force behind the interaction between China，Russia，and Iran is to resist hegemonic bullying led by the United States，jointly safeguard regional stability and prosperity，and advocate respect for diverse civilisations and harmonious coexistence. Within the framework of the SCO，the benign interaction between China，Russia，and Iran is conducive to enhancing political mutual trust and mutual understanding among regional countries，jointly addressing security threats represented by “three forces”，bridging the gap caused by the disruption of international and regional industrial chains due to the COVID-19 pandemic and geopolitical crises，deepening economic cooperation among member states，and promoting the construction of a community with a shared future for the SCO.