Loose sediment is the main material form of overburden， which is the main research object to promote green development and build ecological civilization. With the continuous enrichment of research content， the depth and accuracy in overburden survey are constantly increasing. Whether the accurate and in-situ pollution-free sampling of loose sediments can be realized is one of the key factors restricting the follow-up research. Based on the drilling survey practice in the Xilin Gol League-Tongliao area， this paper combines wire-line coring drilling technology and advance coring technology with film-forming wall protection drilling fluid technology to improve the stability of hole wall and the integrity of loose core so as to solve the technical difficulties restricting the drilling sampling of thick overburden， and provide technical support for loose sediment survey in related fields.