Abstract: This article provides the technological experimental method and the result for the 500 kW automobile axle butt welding machine. The equipment adopted a computer system ot control the welding process and used the preheating Flash Butt Welding(FBW) technology to set qualified joints. This article introduced the Welding machine's output characteristics and its simulation welding experiment in detail. Moreover, it precisely analyzed the preflashing, precheating, flashing and upsetting processes as well. In the experiment, the authors under toolk the experiment by way of analyzing welding processes step by step, that is, to test each step until setting a satisfied result, then go to the next step and finally tested the whole welding processes. It also provided and analyzed some of the key data in this process. At last,a group of the welding parameters of the joint has been presented, which was proved by the mechanical experiment.