Abstract: Abstract: Owing to the higher annual solar radiation and the thinner atmosphere compared to the plain area, plus and minus temperature appear alternately day and night in the Qinghai-Tibet Plateau. Therefore, concrete cast in the Qinghai-Tibet Plateau should have an excellent anti-frost durability. However, current proposed approaches to quantitatively evaluate the number of freeze-thaw cycles of concrete per year are mainly based on the freezing-thawing environment of the plain area. In this paper, firstly in order to compare the freezing-thawing environment difference between the Qinghai-Tibet Plateau and plains, according to the determining criterion of freezing-thawing environment listed in Code for durability of concrete structure, 3 groups of cities from different areas located in the Qinghai-Tibet Plateau and the plains respectively were selected, which had the same freezing-thawing environmental grade. In the meanwhile, because the freeze-thaw damage of concrete usually takes place on the surface and physical thermal parameters between concrete and soil are nearly equal to each other, the land-surface temperature is in good agreement with the concrete-surface temperature. Then the land-surface temperature was utilized to replace the concrete-surface temperature, and the air temperature and land-surface temperature of the 3 groups of cities were compared. The results demonstrate that in the Qinghai-Tibet Plateau the number of freeze-thaw cycles of concrete per year is more, the diurnal range of temperature is much larger and the lowest temperature is much lower than those of the plains. Due to without considering the freezing-thawing environmental difference between the Qinghai-Tibet Plateau and plains mentioned above, it was found that current calculating methods could underestimate the number of freeze-thaw cycles of concrete per year and are insufficient for durability design for concrete in Qinghai-Tibet Plateau. Based on the above analysis, the quantitative method for the freezing-thawing environment of concrete in Qinghai-Tibet Plateau was proposed. In the method, the concrete-surface temperature was replaced by the land-surface temperature and the conditions for occurrence of freezing-thawing damage of concrete were that the uninterrupted time of lowest temperature of less than or equal to -3 ℃ and temperature of more than 0℃ were not less than 2 h respectively. Then, the number of freezing-thawing cycles of concrete per year in Qinghai-Tibet Plateau was counted on the basis of corresponding meteorological data from 20 weather stations in 1971-2003 using the method mentioned above, and a calculation formula, related to the average temperature of the coldest month and annual solar radiation, was created to calculate the number of freezing-thawing cycles of concrete per year in the Qinghai-Tibet Plateau by regression analysis. With the formula the number of freeze-thaw cycles of concrete per year in the main region of the Qinghai-Tibet Plateau could be estimated approximately. The results indicate that in the Qinghai-Tibet Plateau the number of freeze-thaw cycles of concrete per year is generally more than 150, and even reaches 200 in some regions. Therefore, the demand for the durability of freezing-thawing resistance of concrete constructed is more exigent in the Qinghai-Tibet Plateau than in the plain. Based on the quantitative method for the frost environment of concrete in Qinghai-Tibet Plateau proposed in this paper, the design process method for the freeze-thaw durability of concrete structure and the recommended design grade of freezing resistance for concrete in the Qinghai-Tibet Plateau are given at the end of this paper.