Abstract: The development of in-situ marine observation facilities for investigation of the engineering mechanics properties of seabed soil is critical to marine engineering programes. Practical application requires that the in situ measurement equipment must be characterized by short survey cycle, wide measuring range, and the testing results are closer to the true environmental features. However, in-situ investigation facilities as such are poor developed in China. In this paper, we described the engineering mechanical properties of marine sediment need to be measured, discussed the major requirements of in-situ testing, and introduced in details the measurement methods for engineering mechanical properties of seafloor sediment,including offshore CPT, dynamic cone penetration equipment, expendable bottom penetrometer, full-flow penetrometer, flate dilatometer testing for reference. Hope it will be beneficial to the development of the offshore in-situ testing business in China.