Water-based drilling fluid for stabilizing shale

The invention provides water-based drilling fluid for stabilizing shale. The drilling fluid is formed by mixing sodium-based bentonite, a shale inhibitor, a tackifier, a flow-pattern adjusting agent, a filtrate reducer, a high-temperature-resisting processing agent, a bridging agent, bridging particle and an anti-collapse agent. Calculated by the addition quantity in every 100 parts of water, the water-based drilling fluid comprises the following components in parts by mass: 5 parts of sodium-based bentonite, 1.5 to 1.8 parts of shale inhibitor, 0.5 to 0.7 part of tackifier, 0.1 to 0.2 part of flow-pattern adjusting agent, 0.7 to 0.9 part of filtrate reducer, 2.3 to 2.5 parts of high-temperature-resisting processing agent, 9.33 to 10.67 parts of bridging agent, 1.8 to 2.2 parts of bridging particle and 1.1 to 1.3 parts of anti-collapse agent. The drilling fluid is good in rheological property, filtrate reduction property and lubricating property and strong in inhabitation property, so that the requirement of the shale gas horizontal well drilling cuttings carrying and wall stability requirement can be met, and the probability of drilling seizure can be reduced.