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Based on the meteorological data of Sichuan Province from 1961 to 2019 and the drought data of the counties from 1991 to 2019, this paper adopts the information diffusion method to analyze the spatial distribution of drought duration， economic loss rate, crop drought rate and the rate of population exposed to drought for the 10year and 50year return periods. The extreme model based on the generalized Pareto distribution is used to analyze the Possible Maximum economic Loss rate (PML) under different confidence levels in seven arid climate zones of Sichuan Province. The results show that: (1) For the 10year return period, the drought durations are relatively short, about 60 to 80 days in the northeastern, central and western parts of the Sichuan basin, but longer, about 100 days in the Panxi region, southern Sichuan basin and Longquan mountains. For the 50year return period, the drought durations are relatively short, about 90 to 120 days in the Jialing River basin, Fujiang River basin, Dujiangyan irrigation area, central Ganzi prefecture and northwestern Sichuan Plateau, but longer, about 150 days in the Panxi region, southwestern and central Ganzi prefecture and southern Sichuan basin. (2) For 10year and 50year return periods, the drought rates of crops are higher than 60% and 90% respectively, in the northern part of the western Sichuan Plateau, the northeastern and central parts of the Sichuan basin. In the Panxi region and Chengdu Plain, the drought rates of crops are less than 60%. (3) For the 10year and 50year return periods, the rates of population exposed to drought in the western Sichuan Plateau and the northeastern, central and southern parts of the Sichuan basin are over 60% and 80%, respectively. (4) For the 10year and 50year return periods, in the Panxi region, the western and southern Sichuan basin, the economic loss rates are less than 3% and 5%, respectively. In the western Sichuan Plateau and the northeastern and central part of the Sichuan basin, the economic loss rates are higher. Especially for some areas in the northeast Sichuan basin and northwestern Ganzi prefecture, the loss rates are larger than 10% and 20%, respectively. (5) At different confidence levels, the PMLs of Zone IV (the northeastern Sichuan basin) and Zone V (the northern Ganzi prefecture, the central and western Aba prefecture) are quite different and obviously higher than those of other five zones, with the maximum values of 28.5% and 38.6%, respectively; The PMLs of Zone VII (the southern Ganzi prefecture and the northern Panxi prefecture) have the minimum difference under different confidence levels, and the minimum difference is 3.1%. The PMLs of Zone I (Chengdu Plain) are small under different confidence levels and the overall difference is not significant.