Abstract: The southern steep slope belt of Biyang depression has the characteristics of big formation dip,coarse conglomerate and glutenite reservoirs. In parts of the reservoirs,basement rock needs to be drilled down. Because of the complicated geologic characteristics,great difficulty in controlling well bore quality,many down-hole failures and low penetration rate,a comprehensive supporting technology research has been carried out. In the end,bit optimization,drilling pa-rameters optimization and well bore quality control,drilling fluid system selection and underground failure prevention technology have been formed. This kind of supporting tech-nology has been applied by 22 wells,with 47. 78% average shortened drilling cycles,29. 86% increased average penetra-tion rate and 2. 6% decreased down-hole failure rate,andachieved good application effect and economic benefits.