Water inrush is one of the most frequent and harmful geological hazards during tunnel construction, especially in deep-buried and long tunnels. Given the complexity and uncertainty of the geological conditions along the deep-buried and long tunnels, a small-scale mathematical interval is used to quantify the evaluation indices rather than a certain value, and an attribute interval assessment method for tunnel water inrush is proposed. Firstly, considering the hazard-pregnant and hazard-causing factors of water inrush occurrence, the formation lithology, unfavorable geology, groundwater level, topography and geomorphology, attitude of rock formation, contact zone of dissolvable and insoluble rocks, and layer and interlayer fissures are selected as the evaluation indices. Then, the single-index attribute measure functions are constructed to calculate the upper and lower limits of each evaluation index belonging to the four risk levels. The fusion function of multi-index attribute measure intervals is established, and the most probable risk level is identified. Meanwhile, a new comprehensive weighting method for risk assessment of tunnel water inrush is presented by combining the frequency statistics method and triangular fuzzy number theory-analytic hierarchy process (TFN-AHP). Finally, the proposed method is applied to the Yunwushan Tunnel. The evaluation results agree well with the actual situation, which verifies the practicality and feasibility of this method and provides a basis for the risk control of geological hazards in tunnel engineering.