Abstract: The powder of persimmon peel was used as water-based drilling fluid addictive, and the performance of it was evaluated. The results showed that persimmon peel performed a great effect of reducing fluid loss, and with the treatment temperature increasing, apparent viscosity and plastic viscosity was firstly increased, then reduced, and finally increased, the filtration reduction weakened and invalided above 150℃. The results of linear bentonite swelling experiment and mud ball experiment presented that water extract of persimmon peel can inhibit hydration and swelling of clay along with the concentration, excelled to that of 4%(wt) KCl solution. The results of compatibility with common drilling fluid additives showed that the viscosity and filtration reduction increase along with the treatment temperature increasing companying with modified starch, while the compatibility with polyacrylamide is poor, especially, the viscosity drops suddenly (from 30.0 mPa·s to 4.0 mPa·s) at 120℃ and filtration reduction is invalid.