Global warming lead to universally high temperature in summer. Traditional avoid summer heat in the mountains has been unable to meet the public demand for cool climate environment. This paper, focusing on summer tourism in high-latitude of China, selected 212 cities long- term climate observation data from 1980 to 2010, quantitatively evaluated summer climate comfort degree of cities to the north latitude of 40°N by THI, WCI, and ICL. Conclusions are as follows: 1) From the spatial distribution, vast northeastern plains are suitable for summer tourism. In mountainous region of northern Inner Mongolia and Xinjiang, the regions appropriate for summer tourism are small. From time series, the most comfortable time being June with average index is 7.62, next is August with average index of 7.28, July has the relatively poor climate comfort and its average degree is 6.81. 2) The longest avoiding summer heat period is more than 60 days, which includes Heilongjiang, Jilin, Liaoning and Xinjiang Altay region.Second is northern Hebei and central Inner Mongolia, Xinjiang Yili region, the summer heat avoiding period is 30 to 45 days. However, in western Inner Mongolia, Xinjiang Tianshan valley the period is less than 30 days. Among a year, the longest comfortable month is August with average days adding to 25.1, next is July with average days about 20.2, the shortest climate comfortable time is June with average days about 19.9. 3) The high- latitude summer tourism comprehensive regionalization in China is divided into six types. From the type of statistics, the more suitable summer tourism regions are mainly distributed in the high latitudes of centraleast China, and the most competitive provinces are the three northeastern provinces of China.This research provides a certain reference for the choice of summer tourist destination and the formulation of summer tourism development strategy.