The invention discloses a high-temperature-resistant high-density solid-phase-free formate drilling fluid system. The drilling fluid system is prepared from the following compositions in percent by mass: 0.8-1.1% of a tackifier, 0.5-1.0% of a filtrate reducer, 1-2% of a first temporary blocking agent, 1.4-2.2% of a second temporary blocking agent, 0.4-0.9% of a buffering agent, 0.1-0.4% of an anti-oxidant, 45-87% of a weighting agent, and the balance seawater. The system density is 2.0-2.3 g/cm<3>. The drilling fluid system possesses the temperature resistance reaching to 200 DEG C and the density up to 2.3 g/cm<3>, and possesses relatively strong stability, inhibition property, lubricity, storage-layer protection property, degradability, no toxicity and harm to environment under the conditions of high temperature and high density.