Abstract: The theoretical analysis shows that the initial gas emission flow from borehole is related to the drilling radius, drilling depth, drilling time, ground stress, strength of coal body and gas pressure. Five sets of typical coal samples were collected, and five other variables were fixed, and a self-developed experimental device for initial gas emission flow from borehole was applied in this research. After 50 times of test, 48 sets of valid data were collected. Based on the experiment, it has been found that the initial gas emission quantity from borehole is the sum of the unit length of the initial gas emission flow from borehole and approximate proportional to the gas pressure. In another word, the higher of gas pressure, the more of initial gas emission quantity from borehole. Furthermore, in the same condition of gas pressure, the initial gas emission quantity from borehole by being filled with CO₂ was much more than that by N₂. Hence, it could be concluded that the change of the initial gas emission quantity from borehole can reflect the change of coal seam outburst risk.