Abstract: It is a small amount of complex calcium and silicate-aluminates industry wastes(DM) that reduce the influence of harmful compound in phosphorous slag on cement physical performance.The paper studied the hydraulic mechanics with XRD,SEM and MIP.It showed that,when DM was added in phosphorous slag,setting-time became shorter apparently,and early strength higher.Simultaneously,under mechanical activation,the modified result was obvious.Setting-time of the modified cement dramatically shorted to about 8 hours,and early strength enhanced higher than 50%. When DM was added in phosphorous slag,the influence of harmful compound was eliminated, phosphorous slag activity was activated,hydraulic course was accelerated,And it is the effective way to modify phosphorous slag.