The current study monitored nine international social media websites during January 2015 to December 2015. It showed that international social media paid high attention on China issues in 2015. Twitter was the major social media domain of China-related public opinion. March，July，and December was the peak of the public opinion. Politics，international relations，social livelihood，and economics were the four main topics on international social media platforms in 2015. There was a majority of neutral reports，with positive reports focused on sports，education，technology，culture，and tourism while negative reports lies in religion，ethnicity，politics，environment，and social livelihood. The diffusion rules of China-related public opinion on international social media can be summarized as the following：（1）attention on the events occurrence was the main drive of diffusion，（2）reprint was the major source，（3）US，UK，and France monopolized the information stream about China，（4）the international influence of the Chinese first-class media has increased.