Some geophysical methods are used to detect the bottom simulating reflector (BSR) in investigation of marine gas hydrate resources, and then the distribution scope and depth of gas hydrate is identified according to the position of BSR. But drilling samples demonstrate that BSR can not entirely and accurately reflect the depth of gas hydrate. A new type of combined wireline drilling tool has been developed, which can not only use logging-while-drilling tools to detect formation resistivity to determine whether gas hydrate exists in the formation, but can also be switched to wire-line core samplers to take cores by use of the wire-line fishing system. Through design, trial-manufacture and laboratory tests, the feasibility of the gas-hydrate detection and drilling sampler has been verified, which lays a foundation for the subsequent field experiments.