This invention relates to a measurer for oceanic sediment thermal conductivity in-situ measuring system, which comprises: a measuring probe, an attitude detection circuit, a thermal impulse excitation circuit, a temperature collection circuit, a CPU, I/O, and a memory. Wherein, the measuring device comprises: a. a memory; b. an input device; c. a detection device; d. a calculation device to calculate the thermal conductivity by formula k=0.029275*Q/(Tmtm) and store the data in an EFPROM; e. an output device. This device improves measurement precision by filter, high-bit A/D conversion and complex algorithm, cuts time to 1~2min, and has simple structure with light weight for convenient communication.