Taking oily sludge as the research object,this paper conducted solidification experiments with fly ash, clay, and laboratory?made liquid binder as a composite binder.It explored the effects of dosages (mass fractions) of binder components on the solidified block strength and determined the optimum dosage of the curing agent. The results show that the strength of the solidified block is the best in the case of the fly ash dosage of 30%,the clay dosage of 10% and the liquid binder dosage of 5%. Under the optimal process conditions, the cold strength of the solidified block is 2.19 MPa and the hot strength is 2.21 MPa, which indicates that it has sufficient cold strength and thermal stability. The forming mechanism of the solidified block was studied with the help of Fourier transform infrared spectroscopy (FT?IR),X?ray diffraction (XRD), and scanning electron microscopy (SEM). The forming mechanism of the solidified block was put forward according to the characterization results.