Abstract: The paper took Ⅱ₂ seam of Juji coal mine in Yongxia coalfield as an example. On the basis of measuring lots of gas parameters, the adsorption characteristics were studied, gas content and prediction indexes were measured and their relations were studied. The paper comparatively studied the critical value of original outburst gas content. Through the test, the relationships of adsorption index of drill-cuttings △h₂, gas pressure, gas content and destructive type of coal were studied. Eventually, it was determined that the critical value of gas content was 9.0 m³/t, which had been verified in practice. This provided a scientific prevention of coal and gas outburst and improved mining efficiency for Juji coal mine.