Research conclusions ； (1) The equilateral triangular network is generally used for the configure of the blast holes when the diving drill is adopted for the open - air blasting of the roadbed rock. It has the obvious advantages that the blasted rock blocks are even with the small amount of the under-blasted and over - blasted rocks. (2) The configuration of blast holes and the distance between the hole rows are closely related to the the diameter of aperture. Regarding to the diameters of the rock and drill ( diameter of aperture) , there is a reasonable range for the distance between the two ad?joining hole rows. If the distance of hole configuration exceeds this range，the flying rocks，larger rock blocks and even hopper blasting may happen in blasting. (3)This research result is available for the open - air blasting of the roadbed rock with a good effect.