The effects of char pores on char combustion has been studied with fractal theory. The fractal properties of different char samples were derived from mercury porosimetry measurements. Gas diffusion in pores affects combustion in char pores and this diffusion is affected by the geometrical complexity of pores. To explore gas diffusion and combustion in fractat pores, a fractal geometrical factor beta is defined with pore fractal dimensions and other fractal geometrical factors. It has been found that both apparent activation energy and pre-exponential factor have linear relations with the factors beta and the char combustion can be modeled with the fractal geometrical factor.