This paper tests and analyzes the pore character of coal reservoirs in Yichuan area by using Quadrasorb SI Automatic low nitrogen adsorption instrument. The results of this experiment have revealed that the pore types of coal reservoir in this area are mainly microporous. Beside,the microporous is mostly comprised of one closed and airtight type II pores while small pore mainly consist of opend pores of type I and ink bottle shape hole. Moreover,based on the datas of adsorption test of nitrogen in low temperature, the relationship between fractal dimension of pores in Yichuan area and adsorption parameter are analyzed. The results show that fractal dimension D has some relevance with VL and PL,that is fractal dimension D is associated with positive relationship between Langmuir volume and Langmuir pressure to some extent. Yichuan area is a significant exploration area of deep coal seam CBM, thus this research will have an important meaning to the exploration and development of coalbed methane in this area.