This paper points out that the coal-bed methane can not only cause gas outburst and explosion, but is also the greenhouse gas. At the same time, methane is un-renewable clean energy. In order to exploit methane effectively, the numerical simulation method was used to investigate the stress distribution and evolution during the process of mining the upper protective coal seam. The results match well with the filed experiment. The result revealed that the stress drops significantly and the cracks are much more developed in the “core stress relieved area” within 10 m in front of the coal face and -30 m behind the coal face, where the methane extraction concentration is usually more than 60%. The results have important significance on methane exploitation.