Deep foundation pit engineering is a large and complex system engineering，and its safety evaluation is influenced and controlled by many uncertainty factors，which has the characteristics of limited interval distribution of evaluation indexes and fuzzy grade boundaries. In order to reduce the adverse effects of randomness and ambiguity of boundary information of foundation pit safety evaluation index on the evaluation results，a comprehensive evaluation model of foundation pit safety based on finite interval cloud theory was constructed.According to industry standards and related research results，the evaluation index system and classification criteria of foundation pit safety were determined，and the cloud digital features of each evaluation index belonging to different classification levels were calculated.The cloud model was generated by using MATLAB programming software with the positive cloud generator of limited interval.According to the measured data of the sample，the degree of certainty of each security level was calculated.Analytic hierarchy process (AHP) is easy to calculate and the results are clear，but the process of judgment matrix subjectivity and consistency checking is complicated.Entropy weight method can determine the weight according to the degree of index variation，which can avoid the interference of human factors.However，it strictly follows the mathematical rules and often ignores the intentions of decision makers.Therefore,after considering the advantages and disadvantages of two methods，the game theory was used to optimizes and fuses the weights obtained by AHP and entropy weight method.Considering the subjective and objective factors comprehensively，the combination weights of each evaluation index for foundation pit safety were defined.The comprehensive determination degree of the evaluation object was obtained by combining the single factor determination degree of the index value belonging to each safety grade.Finally，the safety grade of foundation pit was determined according to the principle of maximum membership.This method was applied to engineering practice，and compared with traditional cloud model and extension method in the evaluation process.The results show that the model has good feasibility and validity in the study of foundation pit safety evaluation.The results obtained by this method are consistent with those obtained by extension method，which is in line with engineering practice.It overcomes the drawbacks of traditional cloud model when the index values are far from the expected values of both ends of the cloud.It can also provide a new idea for the study of foundation pit safety evaluation.