Abstract: In Lianyungang area, there is much marine soft soil which is of low bearing,high compression and high natural water content．Several methods are used to test the improvement effect of DlM (Dry Jet Mixing)for marine soft soil ground．These methods include the standard penetration test(SPT)，the unconfined compression test of boring samples，and the static loading test of composite ground．The relationship between SPT blow counts and the strength of unconfined compression is established ．The results show that SPT is good method for testing quality of DJM piles．