Abstract: To explore the brittleness and its anisotropy of deep coalbed methane reservoir, the effects of parameters such as the total content of organic matter and clay and the preferred orientation degree, equivalent porosity and pore aspect ratio on the brittleness of deep coalbed methane reservoirs were analyzed. Firstly, 20 primary structural coal samples from No.8 coal seam of Taiyuan Group were collected to carry out microscopic observation, physical property experiments and ultrasonic velocity experiments. Then an anisotropic rock physics model of the deep coalbed methane reservoir was constructed based on the experiment results and microscopic observation. Finally, a two-dimensional brittle rock physics template is established. The results show that the brittleness of coal samples has obvious direction dependence, and the brittleness of parallel and perpendicular lamination directions are correlated. The difference of Young's modulus between parallel and perpendicular laminations is positively correlated with the difference of velocity, and the anisotropy of Poisson's ratio and brittleness index is negatively correlated with the velocity anisotropy parameter. The validation of experimental data shows that the petrophysical model constructed in the paper can effectively portray the influence of coal components and structure on the brittleness characteristics of the reservoir.