Abstract: Using the daily precipitation data from 95 meteorological stations in southwest China from 1971 to 2020, based on the Precipitation Concentration Index (PCI), the Rainstorm Disaster Concentration Index (PDCI) is constructed. The spatial and temporal distribution characteristics of the PDCI in southwest China are calculated and analyzed, and the relationship between the PDCI values and the atmospheric circulation index in the study area is discussed by using the cross wavelet transform and wavelet cross transform methods. The results showed that the PDCI in the study area showed an increasing trend with an increasing rate of 0.09/10a, and the probability of rainstorm disaster increased. The PDCI of three-quarters of the sites in the study area continued to show an increasing trend, and the occurrence of heavy rain disasters would become more frequent. In Southwest China, there were resonance periods between PDCI and AO, NAO, NINO1+2, NINO3.4, NINO4, PDO and SOI. However, there were some differences in the correlation in different time domain. The correlation coefficient between PDCI and atmospheric circulation index fluctuated from −0.27 to 0.31. It is shown that the atmospheric circulation index is an important factor affecting the change of rainstorm disaster concentration in Southwest China.