The expect for the open of Northwest Passage in the Arctic under the climate change would bring favorable chance for our energy strategy development, while the complexity and uncertainty of social and political effect and the impact of climate changes may expose the passage to some underlying risks and challenges. This paper would study the impact of global climate changes on the Northwest Passage and the risk assessment of Northwest Passage based on the theory and method of risk analysis. The potential factors which affect the Northwest Passage in the context of global climate changes are analyzed. And the risk analysis index system is established to evaluate the natural disaster risk threat of the Northwest Passage quantitatively and comprehensively.