Once a high-rise building fire will cause serious casualties and huge loss of property, meanwhile, it will also have bad social impact. In order to avoid or reduce the occurrence of fire, effective prevention and control of high-rise building fire has become an important subject. Building fire risk assessment is the basis of building fire risk management, fire risk assessment of buildings can effectively prevent the occurrence of fire accidents and control the loss of the accident. Based on the study of the role and relationship of all factors in building fire safety, this paper establishes an index system for fire risk assessment of high-rise buildings , which can be evaluated from five aspects, it includes the active fireproofing ability of building, passive fireproofing ability of building, fire fighting and rescue ability, evacuation capability and fire management level. Considering the relationship between the measured value and the evaluation index range from the point of view of system security, the corresponding weight system is determined. Considering that the fire risk assessment of high-rise buildings is characterized by many evaluation parameters, fuzzy evaluation conclusions and complicated evaluation process, in this paper, based on the traditional fuzzy evaluation model, the set value statistics method is introduced in the fuzzy mathematics, and the corresponding evaluation interval is redefined. it adopts the Linear interpolation method to show the evaluation results which is expressed in membership degree in quantitative form, and a new linear weighted average fuzzy comprehensive evaluation model is established. The evaluation results of the new model are more objective, clear and universal.