The depth of the silt layer in foundation of Shenzhen International Conference and Exhibition Centre reaches 4 m.The design adopted plastic drainage board method and preload compaction method to consolidate the soft foundation.Based on observed data of settlement and pore pressure,the average settlement value reached  21.2% of silt depth, the residual settlement was less than 100 mm, and the degree of induration was more than 90%. The strength of vane of silt after treatment increase by 3 times and the static point resistance by 5 times.So, its lastingelastic modulus can meet the design requirements.