The in situ immobilization of metal-contaminated sediment, using various amendments, has attracted great attention owing to their cost-effectiveness. The present study investigated the effectiveness of Chinese loess on Cu, Zn, Cd and Pb stabilization by decreasing their bioavailability in contaminated sediment. The loess was mixed with the sediment in doses of 0, 0.5, 1, 2, 5, 10 and 20 kg. Approximately 70 d after loess application, the effectiveness was evaluated using the Tessier sequential extraction procedure, single extractants (EDTA-2Na, DTPA, CaCl₂ and HCl), toxicity characteristic leaching procedure (TCLP) and column leaching experiment. The results indicated that the loess can effectively transform Cu from the carbonate fraction into the residual fraction when the loess dose was ≥ 5 kg. Results from TCLP confirmed loess reduced leaching rate of Cu and Zn achieving up to 42.4% and 17.6% reductions, respectively, when compared with untreated sediment. The loess could significantly immobilize Cu and Zn in sediment, and the optimum dose of loess in 10 kg wet sediment was 5 kg. However, loess was inefficient for Cd and Pb immobilization. Correlation analysis showed that these four extractants and TCLP extraction method can provide a good indication of the toxicity of Cu, Zn, Cd and Pb in the amended sediment. Column leaching experiment showed that heavy metal in the loess-amended sediment migrated vertically, and the Cu concentration in leachate of the columns in this study will not cause pollution to groundwater within at least 7 years. These results highlight the potential for using Chinese loess as in situ sorbent amendment for sediment remediation.