Abstract: The mechanical properties of closed-cell aluminum foams, which are used as an adjusting device in the novel vertical adjustable isolation bearing proposed by the research team, significantly affect the feasibility of the novel isolation bearing. In accordance with the demand of mechanical properties of the novel vertical adjustable isolation bearing, the mechanical properties of closed-cell aluminum foams under monotonic compression were studied. Three different diameters and three different height-diameter ratios were considered, and the porosity was controlled in the range of 65%-80%. Herein, a total of 18 kinds of closed-cell aluminum foam specimens were designed. The experimental results show that the deformation process of closed-cell aluminum foams under monotonic compression can be divided into three phases, including a linear elastic stage (corresponding to compressive strain of 0%-6%), a plastic plateau stage (corresponding to compressive strain of 6%-60%) and a densification stage (corresponding to compressive strain of 60%-70%). The mechanical properties of closed-cell aluminum foams were greatly influenced by the diameter, by the height-diameter ratio, and by the porosity. With the increase of diameter, the plateau stress increased while the densification strain decreased. With the height-diameter ratio increasing, the plateau stress decreased while the densification strain increased. With the increase of porosity, the plateau stress and energy absorption decreased while the densification strain increased. Finally, based on the test data with a height-diameter ratio of 1 as samples, the linear relationship between the platform stress and densification strain of closed-cell aluminum foams with porosity and section diameter were fitted by statistical regression, and the theoretical formulas of the plateau stress and densification strain of the closed-cell aluminum foam were obtained. The findings can provide a reference for the related research of closed-cell aluminum foams and the design of novel vertical adjustable isolation bearings.