Abstract: This project is mainly concerned about the studies of the return service and modification of finishing agents made from natural vegetable blues,as well as the optimum formula of drilling fluids.These fluids can be used in the following geological conditions:unconsolidated capping,well weathered breaking strata,strata of incompact and breaking core taking rate,and low stability of the borehole walls.To obtain the optimum formula of the novel glue recombined clay free drilling fluids,we use the organic polymers and inorganic cross linking agents,to make the hydroxypropyl guar cross linked.Judging by the field utilization of the fluids,we find out that they possess such properties as low density,large scope of viscosity modification,good rheological behaviors and lubricating ability,and good performances of forming film and protecting borehole walls and cores.Thus,the requirements with regard to the drillings in the Quaternary capping,sandy gravel of loose cementation, and well weathered breaking strata, can be satisfactorily met.