The geological features of China determine the diversity, susceptibility and regional variability of its geological disasters. The occurrence of geological disasters results from the evolution of geological environments, but related closely to multiple factors such as raining seepage, unfreezing, seismic action and human activities. The correlations of some factors is researched which consists of number of geological disasters, casualty, direct economic losses, annual precipitation and precipitation anomaly percentage. A new concept, ratio of coincidence and its computing method, are proposed in this paper. The ratio of coincidence expresses a portion of that the areas with 20% precipitation anomaly matches in susceptible areas of geological disasters. For instance, in 1998, the precipitation anomaly is 10.5% and the ratio of coincidence is 60% in which occurred with great losses. In 2010, the precipitation anomaly is 7.8% and the ratio of coincidence is 65% in which occurred with heavy losses. In 2011, the precipitation anomaly is -9.8% and the ratio of coincidence is 10% in which occurred with lighter losses. In 2018, the precipitation anomaly is 5.9%, but the ratio of coincidence is less than 15% in which occurred with less losses. It is found, total than geological disasters decrease along time, but economic losses increases in single event. There is a positive correlation between the size of the disaster and the triggering factors, especially the ratio of coincidence between the strong rainfall and the geological disaster prone areas is important. Therefore, effective reduction of geological disasters depends on human efforts, but extreme natural force, such as strong raining in a long time, is not neglected in disaster reduction.