With the implementation of the new environmental law and the increasing emphasis on the environment, Swithout landingSdrilling fluid technology has become a necessary condition for drilling in the fragile environment block, Drilling fluid and cuttings need to be treated separately, drilling fluid need reused after maintenance or treated into water. which puts forward higher requirements for drilling fluid system.In order to solve the problem of low solid-liquid separation rate and difficult to degrade, the drilling fluid treatment agent and dosage are optimized, and finally the environment protection drilling fluid system is formed. The laboratory test showed that the filtration loss at high temperature and high pressure at 120 /3.5MPa was 11ml, and the density difference between the upper and lower layers was only 0.0113 g/cm3 after the sedimentation of 24h. The recovery of cuttings was 96.87% and the coefficient of lubrication was 0.15. Environmental friendly environmental performance recovery of drilling fluid is good, BOD, low COD value, easy degradation, EC50 ≥ 36000mg / L, which meet the emission limit standards. The results show that the environmental protection recoverable drilling fluid system has good rheology, stability, pollution resistance, lubricity, inhibition and environmental protection performance. which can meet the requirements of drilling and environmental protection.