Based on the monthly precipitation data from 160 stations in China and the NCEP/NCAR reanalysis data from 1961 to 2016, the interdecadal differences in correlations between the winter precipitation over the southern China and El Niño events and their causes are studied using statistical analysis methods. Results show that: 1) The winter precipitation over the southern China has obvious interannual variations from 1961 to 2016 and presents the characteristics of periodic change with a dry period from 1961 to 1988 and a rainy period from 1989 to 2016. 2) There are interdecadal differences in correlations between the winter precipitation over the southern China and El Niño events during the two periods. In winter of El Niño events from 1961 to 1988, the meridional gradient of geopotential height anomaly at 500 hPa over the eastern China is small, which is not conducive to the southward intrusion of the cold air. The south wind velocity anomaly at 850 hPa over the southern China is very small, it is difficult for the water vapor from the Bay of Bengal and the South China Sea to transport to the southern China, and the southern China is controlled by anomalous downward movement, which is not beneficial to convection development. Therefore, the winter precipitation is less. In winter of El Niño events from 1989 to 2016, the meridional gradient of geopotential height anomaly at 500 hPa over the eastern China is greater, which is conducive to the southward intrusion of the cold air. The southwest wind anomaly at 850 hPa from the northern part of the South China Sea to the eastern China helps transport the warm and wet air from the Bay of Bengal and the South China Sea to the southern China. The southern China is controlled by anomalous upward movement, which is beneficial to convection development. As a result, the winter precipitation is more.