The invention discloses a low-
solid phase ultrahigh-temperature water-based 
drilling fluid which is prepared from the following components in parts by weight: 100 parts of 
solvent water, 3-4 parts ofbentonite, 1.8-2.2 parts of a 
coating inhibitor, 2.3-3.5 parts of a filtrate 
reducer, 2-2.5 parts of high-temperature resistant resin, 2-2.5 parts of a shale inhibitor, 1.5-2 parts of a stripping agent and 15-35 parts of ultrafine 
calcium carbonate. The preparation method is simple. The preparation method comprises the following steps: adding a certain amount of 
bentonite into the 
solvent water toprepare prehydrated 
bentonite slurry; then successively adding the 
coating inhibitor, the filtrate 
reducer, the high-temperature resistant resin, the shale inhibitor, the stripping agent and ultrafine 
calcium carbonate while performing high-speed electric stirring; and finally, carrying out hydration at 
room temperature for 24 hours to prepare the low-
solid phase ultrahigh-temperature water-baseddrilling fluid. The low-
solid phase ultrahigh-temperature water-based 
drilling fluid can 
resist a temperature high up to220 DEG C, the low-solid phase ultrahigh-temperature water-based drilling fluidis good in rheological property, rock carrying property and high in blocking inhibiting property, the problem of 
low density carrying stability is solved, the low-solid phase ultrahigh-temperature water-based 
drilling fluid is successfully applied in mounting and probing a 4X well, and a good field application effect is obtained.