With China’s natural gas in increasing external dependency，scientific assessment of natural gas imports for security risk has become an important content of the construction of the “One Belt And One Road”. In the paper，the present security risk situation of natural gas import source countries are analyzed，and then，an approach and a set of evaluating indicators are presented. Based on cloud theory，security risk levels of main natural gas import source countries are assessed，finally，security risk control policy suggestions on perfect China’s natural gas import source countries is put forward.