Aiming at the stickiness energy of ultra-high performance concrete and reinforcing steel bars, taking the anchorage length of steel bars, diameter of steel bars and thickness of concrete cover as main parameters, the central pull-out tests of ultra-high performance concrete specimens were carried out. The analysis results show that the failure pattern of specimens can be summarized as the pull-out failure, splitting failure and breaking of steel bars. The steel bar diameter has a great influence on the slip at the free end, and has less influence on the bonding strength. In addition, a proposed value for the critical layer thickness was given.