A thermal hazards indices system is built by choosing three aspects

which includes 10 representative indices totally

such as natural environment

permafrost features and pipeline properties.Based on the complexity of hydrogeology and engineering geology of permafrost at KP364 and the ambiguity of index evaluation criteria

a fuzzy comprehensive evaluation model is built by using fuzzy complementary judgment matrix principle to determine the weight.The model is used to assess the thermal hazards at KP 364.It is found that the main factors that induce thermal hazards are as follows:the annual average temperature of the crude oil

the ice content in the permafrost

and the annual average ground temperature.And the risk of thermal hazards is in apoor grade.Wherein

the factor of natural environment

permafrost features and pipeline properties are also in a poor grade.This is consistent with evaluation results in the pipeline around the melting range

which is enlarged year by year.After some indices were revised according to the characteristics of thermal hazards in other typical regions

the model can be extended to other typical regions along the MDL of the CRCOP.