To analyze the influence of different loading rates under reciprocating loading methods on the bending mechanical properties of the socket flexible interface, stepwise reciprocating loading tests were conducted on ductile iron pipes with DN200mm and DN300mm pipe diameters under bending. The effects of different pipe diameters and loading rates on the mechanical properties of the interface were compared. The experimental results show that the bending moment interface angle curve of the flexible pipeline interface has the same trend under different loading rates and step reciprocating loads, and the hysteresis curves of each loading level have good overlap;The variation of pipe diameter has a significant impact on the maximum turning angle of the interface. The larger the pipe diameter,the larger the diameter of the interface rubber ring,resulting in an increase in the contact area between the sealing rubber ring at the interface and the outer pipe wall. The lateral ultimate angular displacement of the two pipe diameters is basically stable at 4°~5°;Obtain the hysteresis curve area for the first reciprocating loading of two different pipe diameters at each loading level. Comparison shows that the larger the pipe diameter at the same loading rate,the greater the energy consumption. However,there is no significant difference in energy consumption within the loading level of 0~72 mm (0°~4°).