Abstract: By comparing the two evaluation methods for the brittleness in coal rocks based on rock mechanical parameters and the radial acoustic velocity variation, the application effect of these two evaluation methods for the fracability in coal reservoirs is analyzed. Through the analysis of examples, it can be seen that the brittleness index of the coal reservoir calculated by rock mechanics parameters is very low, reflecting the poor fracability of the coal reservoir, and ignoring the influence of micro-cracks on the fracability of the coal reservoir. The radial acoustic velocity variation shows that the radial velocity of the coal reservoir decreases most obviously, reflecting the strong fracability of the coal reservoir, which is also consistent with the fracturing effect of the coal reservoir. Therefore, the method for the brittleness evaluation based on the radial acoustic velocity variation can better reflect the fracability in coal reservoirs.