Elbow pipes are widely used in many industries such as petroleum, chemical, metallurgy. Of various elbow pipe forming technology, hot pushing pipe bending process is an efficient and economical one for processing elbow pipes. This paper introduced the technological process and plastic deformation mechanism of hot pushing pipe bending. Four deformation assumptions were proposed to describe the main deformation characteristics in the bending process. The proportional relationship between the bending deformation and the diameter expansion deformation was derived and the horn mandrel was designed. The forming process of the elbow was simulated and the metal flow in the forming process of the elbow was obtained. By using orthogonal experiment, the influence rules of heating temperature, pushing speed, friction factor, bending angle and initial bending radius on the process were obtained, and the optimal process parameters were obtained. It will play a positive role in revealing the pipe forming mechanism and have a guiding effect on production practice.