As the largest log import country in the world, China undoubtedly faces a severe challenge from the reduction in global forest resources. Based on the fact that a flow of ecological elements embodied in the process of import can cause extra ecological stress to the source regions, the authors assessed the ecological effect of China’s log imports on the source countries’ forest sustainability. The ecological footprints embodied in China’s log imports from 1995 to 2010, and then introduce the model of ecological tension index to assess the ecological security status of the forests in major source countries. Results demonstrate that, overall, China’s import of log has posed no serious threat to world forests. Most of the source countries have safe forest ecological states due to their huge forest bio-capacity, although China’s log import has increased their forest ecological stress by more than 14%. While for some developed source countries, China has increased the ecological tension less than 1%. The risk of forests reduction was probably caused by its own resource consumption.