The Tokyo/Haneda International Airport Expansion Project has been progressed to increase runway capacity and reduce jet noise problems. In the project three runways and two terminal buildings were constructed on a man-made island: the first phase was completed in 1988 where a new A- runway was built, in phase 2 a new terminal buildings was constructed and completed in 1993, and in phase 3 construction of two new runways, B- and C-runways, were completed in 1996. A new runway, being constructed, is consisted of a man-made island and a pier structure. Several types of ground improvement techniques were employed in order to increase stability and to reduce the residual settlement of the island; sand drain method, sand compaction pile method and deep mixing method for improvement of natural ground, and pneumatic flow mixing method and super geo-material method for reclaimed land. In the lecture, design and execution of these techniques are briefly introduced as well as the outline of the construction project.