In this paper, the Weaver-Thomas method of mathematical modeling,selected 8 comparable indicator variables (the industrial added value scale,the scale of employment,the scale of the profits, the scale of main business,technical level, the speed of technological progress,discharge coefficient,industrial energy consumption coefficient) and established an actual industrial distribution closest approximation distribution.And then combined with the qualitative analysis,this paper selected competitive strategic industries of Nan'an District. In the end,this paper provided some policy proposals which is beneficial to the small towns of China.