The foundation contains profound extremely dense backfill sand layer and extremely hard silt soil layer in a port project of Singapore，the large HZM/AZ combined steel sheet pile driving is one of construction difficulties in the project. We study the construction characteristics of the combined steel sheet pile，and find that reducing the interlock friction is the key for AZ auxiliary pile driving. We draw up the HZM pile construction precision control standards，and adopt construction sequence of driving auxiliary pile after main pile and construction measures of soil loosen at the middle interlock position，adopt the technology of installation by vibration hammer first then driving to final level by impact hammer for the large HZM pile driving，and optimize the guide frame design. The results show that the deviation and elevation of all pile tops meet the design requirements，and no tearing or disengagement of interlock is found.