Abstract: To resolve drilling problems such as borehole instability and formation damage, low solids for-mate drilling fluid was formulated with viscosifying filtrate reducers, lubricants, inhibitors and formate in laboratory. The research showed that this kind of drilling fluid had a relatively low filtrate volume, low solids content, low friction drag, good inhibitive and pollution resisting capacity, so it could prevent formation damage and stabilize borehole. At the same time, the fluid had a better shear thinning performance, and it could reduce the circulating pressure loss and increase the speed of drilling.