In order to accurately assess the fire risk of urban utility tunnels, an evaluation method based on the improved cloud model and evidence theory is proposed. Firstly, an evaluation index system for the fire risk of urban utility tunnels is constructed from five aspects: fire prevention, fire control, emergency evacuation, personnel prevention and control, and safety management. Secondly, because of the randomness and fuzziness of fire risk assessment, the improved cloud model with cloud entropy optimization is used to calculate the index membership degree. The uncertainty focal elements are introduced to satisfy the basic probability assignment in evidence theory. Then, the improved evidence theory with dynamic and static weights is applied to fuse the information of the evidence and determine the final evaluation results. It avoids the possible paradoxes of the combination of strong conflict evidence in traditional evidence theory and improves the credibility of the evaluation results. Finally, the feasibility and superiority of the proposed method are verified by an example analysis, which provides a new idea for the fire risk assessment of urban utility tunnels.