Abstract: The data are available from the observation of indoor and outdoor air temperature in Kunming City. The characteristics of indoor air temperature in the different weather condition of south and north sides of city buildings were discussed. The result indicates that effect of temperature-increasing on different weather condition is significant. Compared with yard,the increase of indoors minimum and mean air temperature on south-side is 7.7～10.0℃ and 4.6～5.8℃; The increase of indoors minimum and mean temperature on north-side is 4.6～7.0℃and 1.3～4.4℃. It shows that the ability on keep-warm and frigidity-proof of indoor exceaks that of outdoor. Indoor maximum temperature of south-side exceeds that of outdoor,outdoor maximum temperature exceeds that of north-side; the buildings maintain high temperature. In the same time,it weakens the range-ability of indoors air temperature,the daily increase of indoors air temperature is less than outdoor,the daily increase of indoors air temperature on south-side and north-side is 40～48% and 20～30% of outdoor respectively. Time of maximum temperature fall behind by 2 hours in the room than outdoor. It shows that indoor temperature take on lag-time. The indoor relative humidity of south-side is less than that of north-side and the difference of the south-side and north-side is the maximum in cleardays. In the same time,it is minimum in cloudydays. Daily variation of humidity shows that nightly humidity is more than day-time and the nightly humidity variation is less than day-time. This result will be scientific basis for urban climate research and city planning.