The hole wall stability and the flushing fluid leakage are important affecting factors for drilling efficiency and quality in drilling process. The more complex in the hole conditions, the longer the construction cycle and the higher the requirements on flushing fluid will be. The tectonic development is complicated in the construction area in Zaili of South Jiangxi, there are a large amount of loose and poor cemented sandstone, kaoline, chlorite and other water sensitive formations; borehole shrinkage easily occur; the hole wall stability is poor with spalling, block falling and collapse. The test was made on low solid dispersion flushing fluid, good drilling effects were achieved.