Reasonable method of replacing bearings can ensure bridges with obvious bearings diseases to be safely used after maintenance. If the bearings can be replaced under traffic in short time，the influence of con- struction on the traffic can be reduced. In this paper，a method of single-pier jacking-up for replacing bearings is studied，and 27 bridges in a highway in Guangxi Province are taken as examples. The bridge's service condi- tion such as the existing stress at the control section of beam is obtained by finite element analysis and the in- spection and investigation of the bridge construction and maintenance history. Then the stress caused by the dif- ferent height of single -pier jacking -up under different traffic conditions is analyzed. The paper optimizes the method by comparing the result of the present stress in key control section. Finally，it draws a conclusion that if the existing stress of the bridge is appropriate，the method of single-pier jacking-up with reasonable traffic con- trol can replace bearings with no harm to the beam and less influence on the traffic.