In order to study the optimal r atio of cement and calcium oxide by double-mixture solidification for improving dredger fill sludge，the soil modification results by double-mixture solidification were analyzed based on orthogonal experiments.Finally，the fuzzy comprehensive evaluation method was used to quantitatively optimize each ratio scheme.The results show that：① Under the same addition ratio （addition amount of 1.0%?4.0%），there is a positive linear correlation between the optimal moisture content and the addition amount，and there is a negative linear correlation between the optimal moisture content and the maximum dry de nsity.Under non-equal addition ratios，the law is not obvious.However，compared to cement，the water-reducing effect of calcium oxide is better.② The unconfined compressive strength of the sample is affected by the relative ratio of cement and calcium oxide，which is positively correlated when cement and calci um oxide are added in the same amount，but in general，cement plays a major role in the strength growth of soil by double-mixture solidification.③ By taking the fuzzy comprehensive evaluation method and considering various factors such as project solidification construction cost，compressive strength，and compaction characteristics，it is believed that the optimal ratio scheme for dredger fill sludge in Shandong Yulongdao Refining and Chemical Project is 2.0% cement + 1.5% calcium oxide for double-mixture solidification.The optimal moisture content of the sample is 23.3%，and the maximum dry density is 1.68 g/cm3.The unconfined compressive strength is 440 kPa.