The invention relates to a hydroxy-acid salt drilling fluid used in the field of petroleum drilling operations, in particular to a drilling fluid with strong inhibition to water-sensitive clay shale, which essentially comprises 0.1-0.5 percent of hydroxy-acid salt to be used as an inhibitor of the drilling fluid. Metal cations ionized by the hydroxy-acid salt can inhibit the hydration expansion and hydration dispersion of the clay shale; the ionized hydroxyl acid radical anions form protection film on the clay surface through the absorption function between hydroxide radical and the clay surface, thus preventing the hydration of the clay. The recovery rate of the rock debris with less than 5 percent of recovery rate in clear water rolling can be improved to more than 90 percent in the drilling fluid provided by the invention. Therefore, the hydroxy-acid salt drilling fluid is the inhibitory type drilling fluid with simple preparation technology, low cost and no environmental pollution.