Since a large amount of domestic and industrial wastewater containing heavy metals has been discharged into the Haihe River Basin, many heavy metals enter the water environment and accumulate in the sediments. Traditional ecological risk assessment methods ignore the speciation and distribution of heavy metals, leading to the low reliability of ecological risk assessment. This study investigated the plain section of the Haihe River Basin and researched the speciation and distribution of heavy metals in the sediments in the Haihe River Basin and carried out the ecological risk assessment. Sediment samples were collected at the collection points deployed in the Haihe River Basin. Afterward, the samples were processed using mixed acids at the laboratory. Then, the contents of heavy metals in the samples were determined using atomic absorption spectrometry, and the speciation and distribution of heavy metals in the sediments were analyzed. For the ecological risk assessment, abundance calculation was adopted to improve the ecological risk assessment indices and design the ecological risk assessment standard of heavy metals. The experimental results show that the obtained evaluation of the sampling points and various heavy metals were closer to the actual situation, has higher reliability, and displayed better evaluation performance compared to results obtained using traditional assessment methods.