Most probable temperature (MPT) is defined according to the skewed function by using daily average temperature records of the National Meteorological Information Center from 1961 to 2008 in China, it can represent every stations background temperature explicitly. MPT interannual variations show that MPT in summer was relativelly low-temperature-major before the mid-1990s and from then on was warming with fluctuation, but since 2005 the trend slowed down, and that MPT in winter was relatively low-temperature-major in 1961—1986, and from 1987 to the beginning of the 21st century was warming up obviously, but since 2000 the warming trend slowed down. The warming amplitude in winter was stronger than that in summer and the time of beginning of warming in winter was earlier than that in summer by about 5—10 years. Studying three climate states of MPT changes of 1961—1990, 1971—2000 and 1981—2008, we found that in summer MPT got warmer obviously in the third climate state, while in winter in the second state. MPT warming trend was slowing down in the third state. Its worthy of note that in Sichuan, Guangdong and Guangxi MPT even began to decline in the last few years. Whether it means climatic transformation or not needs further research.