Abstract: Abstract: The China-Pakistan Economic Corridor (CPEC) is a pilot and key area of China's "One Belt and One Road" Initiative. Achieving accurate and reliable flood risk assessment in this region was a key issue. Based on the daily precipitation data set in the 0.25°×0.25° grid data set (V1) of the China-Pakistan Economic Corridor, an evaluation index system composed of multiple variables was constructed by comprehensively considering the disaster causing factors, disaster environment, and disaster bearing body, etc. This study proposed an improved game theory coupled with the subjective weight of intuitionistic fuzzy hierarchy analysis and the objective weight based on the index Correlation (Criteria Importance Though Intercrieria Correlation, CRITIC), which can be used to calculate the optimal combination weight. Taking the CPEC as a typical research area to conduct a case study of flood risk assessment and research on its interdecadal evolution characteristics. A case study of flood risk assessment was carried out, and its interdecadal evolution characteristics were studied. At the same time, it has strengthened the research on the index system of risk assessment in the CPEC and the construction of the weight model. In order to obtain theoretical reference and decision support for sustainable development and infrastructure construction in key areas and provided effective information for flood disaster forecasting. The results showed that: 1) By the improved model, the extreme zones of floods were continuously enlarged, and the description of their distribution was more refined and perfect. The flood area calculated in 2010 was 14.9×104 km2, and the correlated coefficient between the calculated flood area and the actual flood area was 0.66. The flood risk assessment method developed was reasonable and reliable, and the evaluation results were basically in line with the actual flood in Pakistan in 2010. 2) The flood risk was greatly affected by precipitation and topography, and the spatial distribution of the flood risk degree was greater in the southeast than in the northwest in CPEC. 3) Medium and high-risk areas accounted for 28.5% of the study area, mainly the areas with small topographic changes, dense river network, and concentrated population distribution, which indicates the attention should be paid to the impact and harm of floods on social and economic development in CPEC. 4) The region's high-risk areas of flood disasters expanded with the interdecadal changes from 1990 to 2010. Changes in the degree of risk over time could be obtained by comparing these results. Among them, rainfall was the most obvious influence factor. Its intensity range and duration were important and played a decisive role in the possibility of flood disasters. Under the conditions of large intensity, wide area, and long duration, flood risk zones of flood disasters will change. The most obvious was the expansion of medium-high and high-risk areas. 5) There were some differences in the scope of flood risk zones in different return periods, but the overall risk trend was consistent. Compared with the high scenario (once in 100 years), the scope of low and medium low-risk areas increased significantly, the scope of medium risk areas expanded slightly, and the area of medium-high and high-risk areas decreased. The decreased areas were mainly distributed in the southern region of the northwest border and eastern Punjab Province. Therefore, it can be concluded that the combined weight assignment based on the improved game theory has realized the optimization calculation of the combination weight under the unit constraint, and the index weight assignment is more scientific and reasonable.