Driven by the new infrastructure of smart city, in order to explore the sustainable development of smart city, this paper starts from the reuse of waste concrete, and studies the mechanical properties of recycled concrete short columns of ribbed thin-walled square steel tube, taking the number of stiffeners and the ratio of height to thickness of stiffeners as parameters. Two types of square steel tube recycled concrete short columns were designed: one with ribs and the other with ribs. The final load capacity and failure mode of ribbed square steel tube recycled concrete short columns were primarily investigated. The mechanical properties of double-ribbed, single-ribbed and non-ribbed square steel tube recycled concrete axial compression short columns were analyzed from the load-displacement relationship. The test results show that the setting of stiffening ribs not only improves the bearing capacity of the specimen, but also effectively slows down the local buckling of the steel pipe. When the width-to-thickness ratio of the specimen is small, increasing the number of stiffeners has little effect on the bearing capacity when the steel ratio remains unchanged. With the increase of the height-thickness ratio of the stiffener, the bearing capacity of the specimen and the stability of the tube wall have an increasing trend. On this basis, the finite element software ABAQUS was used to establish the analysis model. The analysis’s findings demonstrate that the finite element model’s failure mode and load-displacement curve mostly agree with the findings of the experiments.