Based on the NCEP/NCAR reanalysis monthly data from 1951 to 2011 and monthly temperature data at 77 stations in southwest China from 1960 to 2011, the spacial-temporal variability of winter monsoon over Qinghai-Xizang Plateau(WMQXP) and southwestern temperature in January has been analyzed by EOF method. Meanwhile, intensity and location indices of WMQXP are defined. For recent 60 years, WMQXP has significant annual and inter-annual variability. There is an abrupt change of WMQXP in late 1970s from week to strong and mid 1980s from north to south. Under the global warming, the oscillation frequency of the intensity and location both accelerates that the period varies from 7 a to 4 a and from 10 a to 4 a, respectively. According to correlation and synthesis analysis, there exists a close contact between WMQXP and southwestern temperature. When the plateau high strengthens, the intersection between the northern cold air and southwest warm air becomes less than normal, which causes less cloud. Otherwise, abnormal downdraft center appears in the east of southwest China. The whole southwestern region is consistent with higher temperature and eastern part is more obvious. Vice versa. When plateau high is located north, more warm-wet air from the south and cold-dry air from the north join together at the eastern Qinghai-Xizang Plateau. Simultaneously, abnormal northeasterly winds dominate the eastern part of southwest China, and the western part exist abnormal updraft and increases cloud cover. The whole southwestern region is consistent with lower temperature and western part is more obvious. Vice versa. The relationship between the intensity and location of WMQXP and southwestern temperature has great significance to analyze the climate change of the latter.