In order to study the influence of diffusion area on gas emission characteristics, the self-made briquette specimens were taken as the research object. The test was done through sealing coal briquette surface with the self-developed briquette specimens gas emission test device. The results show that the influence of the diffusion area on the gas emission rate of the briquette decreases with the decrease of the diffusion area, but the gap between the values of velocity reduction is gradually narrowed with the extension of the dispersion time. The dispersion velocity curve is approximately L-shaped as a whole, but there is a velocity "transcendence" phenomenon at the inflection point. And it is found that the influence of the two opposite sides of the sealed briquette on the emission velocity is greater than that of the two adjacent faces of sealed briquette and the influence of the diffusion area on the gas emission of the briquette shows that the relation between the cumulative discharge and the time in different diffusion areas is still a finite monotonic increasing function. However, in the same period of time and under different gas pressures, the cumulative discharge is reduced with the derease of the area of briqutte.