Abstract: The author designed a set of technology consisting of "liquid-isolating single-acting double pipe semi-closed pipe coring, the core and pipe wall protection with SH vegetable gum drilling fluid, and Casing Drilling Tool", which can solve the problems such as low percentage recovery of core and core structure damage during the drilling in loose and fractured strata. The drilling liquid of the technology "liquid isolating single-acting double pipe semi-closed pipe coring" is isolated from the inner pipe, which can effectively protect the original core structure from being directly washed dispersedly and damaged, so as to ensure the complete extraction of the cores from loose and fractured layers. SH vegetable gum drilling fluid has the functions of plugging, chip carrying suspension, lubrication, drag reduction and vibration reduction, which can tackle down the leakage and hole collapse of loose and fractured layer. Casing Drilling Tool is used to protect the pipe wall when the casing is run into the hole during the coring with the liquid isolating single acting double pipe semi closed pipe. To realize undisturbed and high recovery coring in loose and fractured formations, a lot of drilling work has been carried out in the working area, which can provide a technical reference for the future coring drilling.