The factors on mechanical anchoring performance of HRB500 steel bars, such as concrete strength, concrete cover thickness, diameter of steel bar, anchorage length of steel bar and transverse reinforcement ratio, were studied based on pull-out tests of 45 specimens. And the formula of mechanical anchoring bond strength for HRB500 steel bars was concluded by statistical regression analysis method. Through the reliability analysis, the mechanical anchoring length of design value and the table of conversion ratio between mechanical and direct anchoring length of HRB500 steel bars have been proposed. So it could be used as a basis for practical projects. The results indicate that the mechanical anchorage length of HRB500 steel bars can be still designed with the formula proposed in GB 50010-2002 “Code for design of concrete structures”.