Abstract: This paper introduces some frequently-used methods with which the authors evaluate the oil tank farms'safety condition: fuzzy comprehensive evaluation, fault tree analysis, DOW's fire & explosion index. The authors mainly introduce the application of fuzzy comprehensive evaluation in oil tank farm. Firstly, the authors decide the main factors that may influence oil tank farm's safety, then the improved analytical hierarchical process is applied to evaluation of these factors' proportion to the safety. Finally, fuzzy comprehensive evaluation model is introduced to carry out a comprehensive evaluation of the oil tank farm's safety conditions. The evaluation is more available, objective and accurate due to the application of the improved analytical hierarchy process, which avoids the identity examination and adjustment of the judgment matrix in analytical hierarchy process.