GHW2 in Ordos basin is an exploration well for shale gas, serious collapsing, rock falling and breaking occurred in the drilling process. According to these conditions, bi-polymer anti-caving fluid system was developed, which has wall protection, inhibitory and cementation properties, and is mainly aiming at the main difficulties encountered in drilling construction in breaking, collapsing, block falling and water sensitive formations. This system was applied in GHW2 with good effects of wall protection and core integrity.