In order to solve the problems of incomplete index system, low accuracy of calculation results and weak applicability of control measures when evaluating the safety of shield tunneling underpasses, a method for evaluating the safety status of shield tunneling underpasses was studied based on entropy weight cloud model. By analyzing various factors affecting the safety status of the project, it was determined that overall safety level was jointly determined by the original safety level of building and disturbance effect of underpass construction process. An original safety status evaluation index system for buildings was established, which consisted of 13 indicators in three categories: the existing deformation resistance of the building, the healthy and intact state of the building, and the importance of building. A safety evaluation index system for underpass construction process was established, which consisted of 22 indicators in five categories: excavation face instability, displacement of soil on side of shield machine ring, subsequent soil consolidation, construction management level, and relationship between building and tunnel. The weights of each index were determined by entropy weight method, the digital characteristics of the index were determined based on the cloud model, safety level and development trend were determined by FSM algorithm, and the weighted fitting weight value was used to judge the primary and secondary risk control points. Taking a subway project under two buildings as an example, the index system and evaluation method were verified. The results show that original safety status of two buildings and the construction process under two buildings are generally safe, and overall risk is within an acceptable range. For secondary indicators that are not inherent attributes of the project, the factors with weighted fitting weight values exceeding the average level (0.04) are used as key control points, those between 0.02 and 0.04 are used as secondary control points, and those between 0 and 0.02 are used as general control points.