[Objective] The flood risk related to cultural relics on protected sites was evaluated in order to provide a scientific basis for improving flood control measures and disaster reduction ability for heritage sites.[Methods] The study used data from 311 cultural relics protection units in Chengdu City, Sichuan Province to determine the distribution law of flood risk for cultural relics protection units. A PSR-SPA model was constructed, and the spatial distribution characteristics of flood risk were determined by spatial autocorrelation analysis.[Results] The flood risk of cultural relics protection units in Chengdu City was high in the west, low in the east, high in the north, and low in the south. Flood risk was higher in the urban area than in the suburbs, and higher in the plain than in the mountains. The flood risk level was positively related to the heritage level. The national key cultural relics protection units had a high risk of flood disaster. The cultural protection units with above medium risk were mainly ancient buildings, important modern historical sites, and tipical buildings. Most of these units were in the areas associated with the Song, Yuan, Ming, and Qing Dynasties. The areas with high flood risk were Qingyang, Wuhou, Jinjiang cities, and other primarily urban areas. There was a weak positive correlation in the spatial distribution of flood risk in cultural and social protection units, and there was a certain spatial agglomeration.[Conclusion] National cultural relics protection sites are vulnerable to disasters, and their ability to withstand disasters should be improved. Attention should be given to flood risk prevention and control for ancient buildings, important modern buildings, and cultural relics protection units in areas associated with the Song, Yuan, Ming, and Qing Dynasties, and give full attention to the early warning, prevention, and control of disasters. Districts and counties threatened by floods should further strengthen the construction of flood control information.