The invention relates to a natural gas hydrate synthesis and decomposition multi-parameter test device which comprises a high-pressure reaction system, a low-temperature cooling system, a parameter test system and a data acquisition system, wherein the high-pressure reaction system comprises a reaction clamp, a vacuumizing system, a natural gas supply system, a saline water supply system, a visualization system and an inlet/outlet metering chamber. The natural gas hydrate synthesis and decomposition multi-parameter test device can both simulate synthesis and decomposition of a natural gas hydrate and test various parameters of the natural gas hydrate, such as the sound wave, the resistance, the mechanics, the synthesis speed, the decomposition gas amount, the porosity, the permeability and the heat conductivity; the mechanics parameters not only comprise a dynamic Young modulus and a poisson ratio which are calculated according to a sound wave test value, but also comprise a static value and the compression strength of the hydrate. The device can also be used for achieving visualization and quick coring functions.