Abstract: Disclosed is a confining pressure-adjustable test and observation system for soil deformation features during vacuum preloading. The system includes a soil vacuum consolidation system, a vacuum drive system, a confining pressure system and a monitoring system; where the soil vacuum consolidation system includes a model box filled with test soil, the confining pressure system is arranged in the model box, two sides of the model box are provided with slide plates, and the slide plates on two sides are provided with expansion control cavities at two side ends of the model box correspondingly, and a corrugated air bag is arranged in the expansion control cavity and is connected to an external air pump and an air bag air pressure control device through a pipeline; the test soil in the model box is covered with geotextile, and the geotextile is covered with a vacuum film.