The invention discloses a device for adjusting and controlling dissolved gas saturation in water under different pressure intensities. The device comprises a closed water storage tank, a liquid circulation module, a test observation module, a pressure module, a dissolved gas concentration measurement module, a gas circulation module and a water tank height adjusting module, the liquid circulationmodule provides circulation liquid for the closed water storage tank, the test observation module comprises a test table for placing samples, the test observation module is connected with the water storage tank and the liquid circulation module, the pressure module is used for measuring and adjusting gas pressure intensity and arranged at the top of the closed water storage tank, the dissolved gasconcentration measurement module is used for measuring the oxygen content in liquid in the closed water storage tank, and the gas circulation module is connected with the top and the bottom of the closed water storage tank through pipelines, so that air of the top of the closed water storage tank is pumped into liquid of the bottom of the water storage tank. According to the device, the dissolvedgas saturation in the water is adjusted and controlled, gas pressure intensity of the upper portion of the water surface is adjusted by the pressure module, relative liquid level and relative heightof the samples are adjusted by the water tank height adjusting module, and the device controls saturation states to keep stable or change.