Hong Kong is facing an increasing demand of reclamation land use. However, we are facing an unstable supply and increasing price of the tradition backfilling material – sand. Therefore, we need to investigate an alternative. Ash-strengthed marine deposit can be a solution. Marine deposit can gain strength after mixing with cement, coal ash and water. This material can also reuse contaminated marine deposit. Therefore, the feasibility of using ash-strengthened marine soil is going to be investigated.