The invention discloses a dynamic loading system for measuring dynamic characteristics of natural gas hydrate sediments and belongs to the technical field of measurement of mechanical characteristics of natural gas hydrate sediments. The dynamic loading system is characterized in that the system is formed by connecting a three-axis pressure chamber, a heat exchanger, an axial loading piston, a hydraulic oil source, a hydraulic actuator, a servo valve, a servo driver, a servo controller, a digital/analog (D/A) interface, a data acquisition module, an industrial personal computer, a load sensor, a displacement sensor, a strain sensor, a low-temperature control system, an internal confining pressure loading system and an external confining pressure loading system, wherein the internal confining pressure loading system, the external confining pressure loading system and the low-temperature control system can rapidly and accurately control the pressure and temperature, so that the experimental requirement of performing in-situ reaction on submarine hydrates in a lab is met. The system has the effects that the dynamic characteristics of the natural gas hydrate sediments can be tested according to the system, important kinetic parameters are provided for safety mining of the submarine natural gas hydrates, and the system is relatively low in construction cost.