According to the characteristics of dredged ultra-soft soil,the innovative vacuum preloading methods including the new surface-layer pretreatment method,the new energy-efficient vacuum pumping method and the new anti-clogging prefabricated vertical drain (PVD) method,etc. are carried out based on the field experiment at Quanwan Port Area of Huizhou City in Guangdong Province,the effect of which is evaluated through shallow pretreatment and deep soft soil treatment experiment by the combined fill and vacuum preloading method.According to the field monitoring and test results,the consolidation effect of the dredged ultra-soft soil are tested from indices such as the vacuum,settlement and pore water pressure combining with the in-situ vane shear test,cone penetration test,and the laboratory soil test.The results prove that the innovative vacuum preloading methods are feasible and efficient for the improvement of the dredged ultra-soft soil in the coastal area.