Abstract：A vast data from the drilling and geophysical prospecting are reliable original data to describe the space state of engineering rock mass，and one of the main difficulties in three-dimensional(3D) modeling of engineering rock mass is the processing of the primary data. In the view of 3D modeling，the engineering rock masses are classified as four basic types according to their geometric characteristics of geologic structure：(1) continuous rock mass；(2) discontinuous rock mass；(3) adverse fold rock mass；and (4) unstratified rock mass. Drilling data are the important data for rock mass description with the characters of multi-scale of the spatial data，and thus the criteria of processing drilling data is established. According to the characteristics of rock layers，the processing method of drilling data for 3D modeling of engineering rock mass is proposed，which includes vertical generalizing rule and layered method of processing generalizing rule for original drilling data. With this method，the data for 3D modeling of engineering rock mass is performed and the model form of engineering rock mass is established. Consequently，3D modeling of engineering rock mass is proposed；and the feasibility of this method is proved to be successful.
