A new shear transfer system for CFST columns is studied, which is an application of the patent EP2305911B1 into the square CFST columns. The new optimized system, called UPCCFST, consists of crown-shaped protrusions on the steel sheet oriented towards the side that remains in contact with the concrete. Initial tests have been conducted to study the failure modes and optimize the design. The optimized design is considered the default characteristic of the experimental campaign, consisting of 56 push-out test specimens. The following parameters have been analyzed: connection system, punch density, concrete type, punch arrangement and cross-section dimensions. The UPCCFST system with the optimum punch density (HD) has shown a steel-concrete shear strength, tu, 12.31 and 2.95 times higher than the conventional flat CFST in 200 × 4 and 110 × 2 specimens, respectively. Regarding the slip energy, the UPCCFST specimens absorbed 8.1 and 3.6 times more energy than the respective flat CFST specimens.