Abstract: Based on the data of daily mean temperature before and after homogenization from 111 meteorological stations during 1961-2017 in He'nan province, the statistical analysis method was used to analyze the changes of annual, seasonal and monthly mean temperature and their spatial distribution before and after homogenization in order to clarify the effects of unnatural factors on the trend change of mean temperature in He'nan province.The results show that from 1961 to 2017, the annual mean temperature in He'nan province increases significantly before and after homogenization.The increasing rate after homogenization is 0.21 ℃ per decade which is 0.02 ℃ higher than that before homogenization.Among the four seasons, the increasing rate of seasonal mean temperature in winter before and after homogenization both are the highest, which are 0.36 ℃ per decade and 0.38 ℃ per decade, respectively.Among the twelve months, the increasing rates of monthly mean temperature in February before and after homogenization both are the highest, the values are 0.49 ℃ per decade and 0.51 ℃ per decade, respectively.Among 111 meteorological stations, 41.4% of the total sites are not affected by non-natural factors, while the rest 58.6% are greatly affected by non-natural factors.For the annual mean temperature, after homogenization, 96.4% of the total stations increase significantly which are averagely 6.3% bigger than that i.e.90.1% before homogenization.Among the rest 58.6% of the total stations, the climatic tendencies of 43.3% and 15.3%are averagely underestimated and overestimated, respectively.For the seasonal mean temperature, 99.1% of the total stations significantly increase in both winter and spring after homogenization, while the percentages are 98.2% and 92.8% before homogenization, respectively.Among the twelve months, the months whose mean temperatures increase significantly in more than 50% of the 111 stations are February, March, April, October and December before homogenization, and January is added after homogenization.The effects of non-natural factors on the mean temperature result in the underestimation of the warming rate in He'nan province.