Abstract: The author took Qinzhou District in Tianshui City as an example, and analyzed the establishment of sample point’s land price-floor area ratio model and determination of floor area ratio (FAR) modification; introduced calculation of floor area ratio in land evaluation briefly as well. The results showed that: (1) correction coefficient of FAR varied in different land use purpose and classification; (2) the growth rate of land price would decrease with increasing FAR; (3) bigger FAR was not always better, the best FAR should be determined under comprehensive consideration of economic, social and ecological benefit. It had provided a basis for the government to improve its land market management level, guide investors and formulate policies.