Abstract: Marine hydrates occupy sediment pores, altering the composition of sediments and affecting the strength of the reservoir, which makes the study on the pore-occupying media vital for extraction site selection and safety evaluation. Low-temperature and high-pressure triaxial tests on hydrate-bearing sediments (HBS) and hydrate-free sediments are conducted to explore the influence of the ratio of pore-occupying media and confining pressure on sediment strength. Results show that the type of pore-occupying media significantly affects the strain hardening and softening characteristics. The deformation resistance of HBS increases with the increment of hydrate saturation, and the peak strength of HBS increases with hydrate saturation until a critical saturation is reached. Meanwhile, the peak strength of the hydrate-free sediments increases with decreasing porosity. Both hydrates and soil particles significantly affect the cohesion of sediments, but through different mechanisms: hydrates enhance cohesion through cementation, while soil particles enhance it through interlocking friction. As the effective confining pressure increases, the pore-filling effect of hydrates gradually weakens compared to that of soil particles. Under a constant total volume of pore-occupying media but with varying ratios of hydrate to soil particles, the strength of HBS initially declines and then rises with increasing hydrate saturation, showing a critical occupying ratio. This critical occupying ratio increases with decreasing effective porosity, reaching 76% at an effective porosity of 38%.