In order to quantitatively evaluate the air temperature affected by roads, two types of roads were selected to do the experiments: one was the State Road with 10 meters wide, the other was the highway with 28 meters wide. The air temperature was measured at 8 points by one side of the road, the distance of the points away from the road from 15 m to 200 m. Wind speed and direction were measured at one of the points, which is 30 m from the road. The experiments were carried out from January to May, 2014, in Shanxi Province. Air temperature, wind speed and wind direction were recorded minutely. The difference of the air temperature among different points is mainly studied. The results are as follows: (1) The road was a heat source for the surrounding environment. The intensity of the heat source varied within a day, with the weather conditions, wind velocity, and the traffic of the road. Usually, it became stronger in the conditions of the sunny days, low wind speed, daytime and heavy traffic flow. But sometimes the intensity of the heat effect at night time was stronger than that in the daytime around the highway in spring. (2) The heat effect added by the traffic flow was 005 ℃ to 01 ℃ on the State Road, which with the daily traffic flow of 150 to 350, while that was 016 ℃ on the highway, which with the daily traffic flow of 2000-3500 (3) The distance by the road influenced to the air temperature was 75 m off the State Road, and 125 m off the Highway. The raising temperature effect was up to 025 to 04 ℃ on the State Road, and 02-04 ℃ on the Highway.