By the application practice of flush fluid for scientific drilling in the Luobusa of Tibet, combining field laboratory tests and mud type, mud formula, performance characteristics and its use in the actual production process, a flush fluid formula is summarized, which suits for complex formations of collapse, broken, serious leakage and hole diameter shrinkage in Chromium iron mining area of Luobusa. The paper elaborates the application of different flush fluids and the existing shortcomings; explains the different effects of mud with the same formula in different drilling conditions, which provide some references to the selection of flush fluid formula for deep drilling in complex formations.