In view of the difficulty in the treatment of geological drilling waste slurry in the current green exploration, the chemical flocculation + mechanical pressure filtration method was used to carry out the experiment. The effects of reagent dosage and pressure filtration time on the dehydration effect of waste slurry were studied, and the process operation parameters were optimized. The results showed that the flocculation effect of 50 mL sampling waste slurry was the best after treatment with 5% polyaluminum chloride ( PAC ) aqueous solution 1 mL + 0.1% polyacrylamide ( PAM ) aqueous solution 2.5 mL. The pressure filtration process was divided into three stages : fast, medium and slow dehydration, and the main dehydration operation was completed in the first 15 min. Under the optimal conditions, the average moisture content of the filter cake was 53.45% and the clarity of the filtrate was good after pressure filtration for 27 min. This study can provide data support and technical reference for the harmless treatment of waste slurry in drilling engineering.