In order to study the bond anchorage properties of steel bars after yielding, the strain distribution of steel bars was measured by the method of slotted steel bar surface and embedded resistance strain gauge. A total of 15 beam end bond anchorage tests were carried out by taking the strength grade of steel bars, the strength of concrete, the diameter of steel bars, the thickness of the protective layer, the ratio of the hoop, and the anchorage length as vari? ables. The test results show that the relative slip of the loading end increases significantly after steel bar yield, the bond stress of the yielding section decreases significantly, and the maximum yield penetration depth is related to the constraint of the steel bar and the diameter of the steel bar. Based on the test results, the formula for calculating the relative slip of the loading end after yielding is obtained by statistical regression. At the same time, a calculation method of the anchorage length after steel bar yielding is proposed, which can effectively calculate the anchorage length after steel bar yielding.