In the process of harmless treatment of waste geological drilling fluid， the waste solid after solid-liquid separation contains a large amount of ground rock powder and fine sand with high water content， as well as a large number of harmful substances such as organic matter， heavy metal ions. In view of the problems with solidification of the waste solid phase in geological drilling， cement was selected as the main agent from three main curing agents： P.O42.5 ordinary portland cement， fly ash and lime； then the basic formula of the curing agent was determined by orthogonal experiment as 25% P.O42.5 ordinary portland cement + 2% PF-3 accelerator +3% RES-1 composite early strength agent， and verified by range analysis. The adding amount of the proppant was also determined at 7%， which can effectively increase the curing strength without increasing mixing difficulty. The curing agent formula was field tested at YK11-2 well for waste drilling fluid treatment with the compressive strength of solidified body up to 1.41MPa， and the pollution index and heavy metal ions meeting the national secondary discharge standard， achieving good treatment effect.