To explore the feasibility of using decarbonized coal gasification slag (DGSP) as supplementary material in concrete,the decarbonized coal gasification slag powder,fly ash (FA) and steel slag powder (SSP) were employed to replace cement to prepare the mortar and concrete samples. The workability and mechanical properties were studied. Meanwhile,the chemical composition,mineral composition and micro morphology of the powders were analyzed by using X-ray fluorescence (XRF) spectrometer,X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that,the existence of globular vitreous body in FA and SSP helps to improve the flowability of the mixture. The slump of the fresh concrete with DGSP slightly reduces to 210 mm with slump flow to 500 mm,due to the rough and porous surface of the particles,resulting in much more water demand,which still meet the working requirements. Moreover,the compressive strength of all the specimens increases with the curing age,in particular,each group reaches over 70% of the designed strength value at 3 d age. The strength of the specimens with SSP increases significantly due to the early hydration of silicate minerals in the powders,while fly ash contains a certain amount of lime and gypsum,which helps to stimulate the activity of glass,and activates the hydration of vitreous materials in FA. Especially,the strength of the specimens with DGSP at 28 d exceeds the designed value by 23%,due to the delayed vitreous hydration next to the hydration of cement,leading to the improvement of the later strength of the concrete. It is explicit that the higher the mass coefficient of the particles is,the higher the activity and compressive strength of the mortar is. However,the compressive strength of the concrete is not only influenced by the activity of the powders. The surface of decarburized gasification slag powder has many edges and corners,which enhances the adhesion between slag powder particles and cement paste,and the flexural pressure ratio of mortar specimen is relatively the highest,leading to the increase of the ratio of bending-compressive strength of the specimens with DGSP by 50% compared with the group of ordinary portland cement at 7 d,and 78% at 28 d.