Accurate and quantitative investigation of the physical structure and fractal geometry of coal has important theoretical and practical significance for coal bed methane (CBM) development and the prevention of dynamic disasters such as coal and gas outbursts. This study investigates the pore structure and fractal characteristics of soft and hard coals using nitrogen and carbon dioxide (N₂/CO₂) adsorption. Coal samples from Pingdingshan Mine in Henan province of China were collected and pulverized to the required size (0.20–0.25 mm). N₂/CO₂ adsorption tests were performed to evaluate the specific surface area (SSA), pore size distribution (PSD), and pore volume (PV) using Braunuer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), and Density Functional Theory (DFT). The pore structure was characterized based on the theory of fractal dimensions. The results unveiled that the strength of coal has a significant influence on pore structure and fractal dimensions. There are significant differences in SSA and PV between both coals. The BJH-PV and BET-SSA obtained by N₂-adsorption for soft coal are 0.029–0.032 cm³/g and 3.523–4.783 m²/g. While the values of PV and SSA obtained by CO₂-adsorption are 0.037–0.039 cm³/g and 106.016–111.870 m²/g. Soft coal shows greater SSA and PV than hard coal, which is consistent with the adsorption capacity (\({V}_{\mathrm{L}}\)). The fractal dimensions of soft and hard coal are respectively different. The Ding coal exhibits larger D₁ and smaller D₂, and the reverse for the Wu coal seam is observed. The greater the value of D₁ (complexity of pore surface) of soft coal is, the larger the pore surface roughness and gas adsorption capacity is. The results enable us to conclude that the characterization of pores and fractal dimensions of soft and hard coals is different, tending to different adsorption/desorption characteristics. In this regard, the results provide a reference for formulating corresponding coal and gas outburst prevention and control measures.