Abstract: In order to ensure the safety of open-pit mine in the process of transportation, this paper attempts to come up with a three-dimensional risk model of open-pit mine transportation system including the possibility of risk occurrence (L), the severity of risk consequences (C) and the time value of risk (E).Aiming at problems that are difficult to quantify in 3D risk models, combining the quantitative values of each level of risk factors, an improved radar chart method is proposed to realize adaptive division of 3D risk evaluation result level intervals; combining the characteristics of the interaction and interconnection of the open-pit transportation system, integrating the relevant quantities of the indicators on the basis of the structural entropy weight method, proposes an improved structural entropy weight method to fully and objectively calculate the indicator weight; considering that the expert evaluation data contains a large amount of uncertain information and it is difficult to analyze it objectively and comprehensively, the fuzzy matter element is improved based on the fuzzy set to support the quantitative expert evaluation data from three aspects of support, opposition and neutral information, and is based on unascertained rational numbers extract support, opposition and neutral information objectively and accurately.An example is given to illustrate that the 3D risk assessment model and its quantification method can effectively reflect the safety risk level in open-pit transportation.This method provides a new idea and method for the risk assessment of the open-pit mine transportation system.