Due to the rapid development of urbanization and the impact of extreme weather, the conflict between urban land use and flood safety becomes prominent while the flooding risk increases. Taking Quxian of Sichuan Province as the study area, we updated the flood level and conduct inundation risk analysis. Using historical flood records and observation data over the past few decades, we established the flood level dataset and re-estimated the flood level in various recurrence intervals by analyzing the distribution of flood frequency and peak flood levels, and the correlation between flood levels at different locations. It was shown that, as a result of extreme weather, the flood levels of the main counties in Quxian have increased by an average of 40 cm compared with historical flood levels, i,e., those of the once-in-100-year, once-in-50-year, and once-in-10-year have risen to 254.75, 253.48 and 250.54 m, respectively. According to the national flood control standard, the central city of Quxian and Sanhui County should be able to resist flood with recurrence intervals of 50 and 20 years respectively, while other counties along the river remain at 10 years. Compared with the current flood control standard, the updated standards could potentially prevent agricultural and construction land from flooding by more than 30 and 7~8 km² respectively.