Abstract: Economic stripping ratio is an important factor that determines surface mine ambit. This paper brought the idea that to determine economic stripping ratio according to the Price Law was more reasonable after a analysis of the principles of calculating economic stripping ratio under the guide of market economy situation. On the basis of the economic stripping ratio calculating formulas according to the Price Law, the author pointed out that the previous formulas did not take lowest profit of surface mines, cost of reclamation, recovery ratio, and safety factor into account. After comprehensively considering the above essential factors that affect sruface mines, the author presented a new concept called reasonable economic stripping ratio, which will give a support to the establishment of surface mine ambit. Based on what are mentioned above, the author suggested to modify the principles that determine surface mine ambit into the one that ambit stripping ratio equals to reasonable economic strippin ratio.