The vacuum preloading method has been applied widely to the compaction of the newly-blown muck in the land reclamation engineering,but the compaction effect shall be improved.Based on Lianyungang newly-blown muck engineering,we propose that the shallow course within 3 to 5 meters range is the key part to be compacted by the vacuum preloading method,the flow silt approaches the critical state after 3 months’ vacuum preloading,and the effect of continuous vacuum preloading operation is not obvious.We then propose to adopt the gas injection method from the view of unsaturated zone to turn the plastic or soft soil into mucky clay with shallow unsaturated zone. Comparing with ordinary soft foundation treatment,the physical and mechanical indexes of soil are improved obviously.