Abstract: Based on the data of monthly mean air temperature and precipitation from about 400 stations in 1951～1995 and the data of maximum and minimum air temperature, relative humidity, total cloud cover and low-cloud cover, sunshine duration, evaporation, wind speed, snow-covered days and depth, and soil temperatures in 8 layers from o m dowm to 3.2 m, from 200 oddstations in 1961～1995, the climate change and its characteristics in China in recent 45 years have been analyzed and studied comprehensively. This paper, as the first part of the work, has analyzed the climate change and regularities of such meteorological elements as mean air temperature, maximum and minimum air temperature, precipitation, relative humidity and sumshine duration. The possible mechanism on climate change in China and the climate change and regularities of other meteorological elements will be discussed in another paper as the second part.