Based on analyses of the sampled mudstone of Well Bincan 1, the REE geochemical characteristics of the Lower Cretaceous mudstone of Suibin Depression in eastern Heilongjiang Province are described. The results indicate:(1)The LREE content obviously enriches compared with the HREE content and with negative Eu anomalies shown in the chondrite aerolite standard pattern of the mudstone. However, the parameters such as the ∑REE content,∑LREE/∑HREE,LaN/YbN,LaN/SmN，GdN/YbN，Eu/Eu*，Ce/Ce* and （La/Yb）UCC ratios are quite different, which reflects the mudstone is from different provenance. The provenance for the Didao and Chengzihe Formations may be the granites in the Huanan Uplift south to the Suibin Depression, the sedimentary rocks in Baoqing area southeast to the depression and the sedimentary rocks in the Dongsanjiang Basin east to it. The provenance of the Muleng and Dongshan Formations may be the sedimentary rocks in Baoqing area southeast to the Suibin Depression and in the Dongsanjiang Basin east to it. During the deposition of the Muleng and Dongshan Formations, some materials may be from the deep lower crust and the mantle and leads to the great change of provenance. (2)The Ce/Ce* and Ceanom indexes indicate that the palaeoenvironment of the Early Cretaceous mudstone in the Suibin Depression was a reduction environment and is profitable for the oil and gas formation. (3)In the Early Cretaceous, the Suibin Depression was a continental margin setting, with a tectonic evolution from active setting, through stable setting to active setting.