Abstract: This paper based on the Pearl River Basin of a dredger fill site case,introduces the construction parameters and the application effect of vacuum preloading,and makes a quantitative analysis of the formation strength in mud deep mixed column.The results show that the vacuum preloading is applicable to these sites,and the reinforcement effect is obvious,but the strength in the mud deep mixed wall decline larger,this position needs to take a replacement for another times after the treatment to use,which can offer some references for other similar engineering.