The related treatment methods of sticking are mainly by up-lifting and down-lowering drilling tool or rotating turntable with external force to make drilling tool to restore free state; by adjusting drilling fluid performance, putting condensed slurry plug, acid injection, grouting pipe freeing agent and reverse circulation to move or damage the infillings between the pipes and borehole wall; by the use of reverse thread drilling tools to fish and even by casing milling to pull out the stuck drill. A serious sticking accident occurred in the drifting process in DPT-305 well of Daniudi gas field, and the final stuck freeing was completed by heavy slurry cleaning fluid, acid injection, pipe freeing agent grouting and pressure holding in annular space; by fixing turntable and moving it up and down to apply torque to the stuck drill and by the use of reverse thread fisher. The causes of the accident are summarized and the analysis on the treatment process is made, which could be the reference experience for similar accidents in future.