Over the past seven decades since the end of World War II，the international security environment has changed greatly and the international security order is faced with new challenges. The double-edged sword effect of globalization，the rapid development of informatization，as well as the emergence of non-traditional security problems and regional hotspot issues，have exerted significant influence on the current international security order and have prompted the new order’s construction，which is underpinned by the changes in the relations between great powers and adjustment of the international order. The construction of new international security order is not “making a fresh start”. Instead，the new order is built on the basic principles which were established after World War II. The new security order will keep abreast of the times and actively respond to new security problems in order to pursue the common security of mankind. At the global level，the United Nations is still at the center of the new international security order. As the United Nations also faces many challenges，reforms are essential to strengthen its position in the international security order. At the regional level，the NATO，SCO，ASEAN，CICA，AU and other regional organizations have made a lot of progress in regional security cooperation in recent years. China has played a positive role in constructing the new order of international security with contribution to both theory and practice.