Fracture parameters are important reference factors for surrounding rock stability analysis.To realize the visualization analysis of surrounding rock fractures，this paper proposed a three-dimensional （3D） reconstruction method of surrounding rock fractures based on the visualization toolkit （VTK）.Firstly，the collected tunnel surrounding rock images were preprocessed by OpenCV for image grayscale and noise reduction.Secondly，the Otsu method and the open operation in morphology were used to segment the image，and the complete surrounding rock fracture map was obtained.Then，the median method was used to replace the linear interpolation method with the traditional Marching Cubes algorithm in VTK to calculate the equivalent point，and the improved Marching Cubes algorithm was used to carry out the 3D reconstruction of the processed fracture image.Finally，the 3D model reconstruction rates of the improved algorithm were compared with that of the original algorithm.The results show that ① by applying VTK to 3D reconstruction of tunnel surrounding rock fractures，a complete 3D model of fractures can be obtained to realize 3D reconstruction of local surrounding rock fractures；② there are no significant differences between the two algorithms in the 3D model of fractures，but the 3D model reconstruction rate of the improved algorithm is increased by 18%.