Xing'anling-Baikal permafrost is located in the southern edge of the Northern Hemisphere permafrost, which is one of the most important regions of permafrost changes. Based on the monthly meteorological data and circumpolar active layer monitoring data in the last few decades, we analyzed the changes in the depth of seasonal freezing (DSF) and the thermal regime of Xing'anling-Baikal permafrost in China, and compared the state with that of the permafrost in Mongolia at the same latitude (LAT). The Xing'anling-Baikal permafrost in China was not connected in the section. The DSF changed between 0.78 and 3.25m. In the study area, DSF was the thickest in Tulihe and reduced to around. The change rate reached -16.0-4.9cm/a and decreased in most areas. The ground temperature raised at a rate of 0-0.41 degrees C/a, whereas that of other few areas decreased with a rate of -0.35 degrees C/a. Freezing duration spanned 141-176days. The changes were related to air temperature, altitude, LAT, and precipitation in the local area. Compared with the state of permafrost in Mongolia at the same LAT, the permafrost in China exhibited a faster rate of degradation. The permafrost in the Xing'anling area significantly responded to climate change. The results will aid in understanding the temporal and spatial variation in local permafrost and provide relevant verification for regional permafrost.
