The invention relates to a high-density water-based drilling fluid for drilling shale and solves the problem of wellbore instability during shale stratum drilling of a water-based drilling fluid. The technical scheme is that the high-density water-based drilling fluid is prepared from the following raw materials: 900-1,000 g of tap water, 30-60 g of bentonite, 2-4 g of Na2CO3, 1-3 g of a drilling-fluid polymer salt-resistant tackifying inhibitor CP-1, 3-5 g of drilling-fluid carboxymethyl starch GMS-1, 10-30 g of high-temperature-resistant special resin SPNH-III, 15-25 g of a high-temperature-resistant viscosity reducer JNT-1, 10-30 g of a lubricative nano emulsion NL-III, 10-20 g of a fluorescence-free white asphalt anti-collapse agent WBF-II and 10-30 g of water-dispersing cationic emulsified asphalt power SFT-I; an alkali solution with the mass percentage concentration of 40% is prepared from NaOH to adjust the pH of the system to 9; a hydrocarbon reservoir protection weighting agent YB-I is adopted to increase the density of the system to 1.8-2.0 g/cm<3>. The high-density water-based drilling fluid is low in cost and high in inhibition performance, causes little reservoir damage and is used for drilling a deep shale stratum.