Abstract: The failure process and failure modes of ultra-high performance concrete (UHPC) stub columns were investigated through the axial compression capacity test of ten groups of UHPC stub columns with diamond-shaped and cross-shaped composite stirrups and one group of columns without steel bars. The effects of stirrup spacing, fiber content and stirrup form on their axial strain-axial load curve and stress-strain curve were analyzed. Results show that increasing numbers of closed loops in the form of stirrups and fiber content could improve the deformed capacity of UHPC stub columns. The effects of stirrup spacing and fiber content on the axial compression bearing capacity and corresponding axial peak strain of the UHPC are significant. The impact of stirrup spacing on the axial peak strain is greater. The peak load of diamond-shaped composite stirrups (DC) with the same stirrup spacing is higher than that of cross-shaped composite stirrups (CC) specimens. As the spacing of stirrups decreases, the slope of the ascending section of the UHPC normalized stress-strain curve of each specimen increases, at the same time the differences of descending sections are more significant. The effects of fiber content and different types of stirrups on the stress-strain normalized curve of UHPC specimens are small. Considering the restraint effect of stirrups and fiber restraint, the calculation formula of axial compression capacity of UHPC short columns constrained by composite stirrups was proposed. The calculation results are in good agreement with the experimental results.