This paper, by means of XRD and TEM, conducts tests in velocity sensitivity, water sensibility and pressure sensibility of the major CBM reservoirs in Dafosi well field according to industrial code SY/T 5358-2010, aiming at reducing damages to reservoirs during CBM development and reaching an efficient development. A moderate damage to velocity sensibility comes from coal powder motion. A big damage to water sensibility is derived from kaolin, which disperses and migrates in the water, and blocks pore throats. Also there is a big damage to pressure sensibility by surrounding pressure; permeability is impossible to recover even if the surrounding pressure is restored. This paper suggests controlling liquid level reduction intensity and liquid quantity, reducing velocity sensibility, decreasing damage to pressure sensibility near wellbore zone, avoiding damage to water sensibility by using drilling liquid and fracturing liquid close to the original coal water mineralization degree.