The invention discloses a radial forging type strain-induced semi-solid extrusion process for an outer cylinder forged piece of an aircraft landing gear. The process comprises the following steps of: preheating a metal bar which is made of super high strength steel or titanium alloy and is used for forming the outer cylinder forged piece of the aircraft landing gear; repeatedly upsetting and lengthening the metal bar to obtain a distorted metal bar with storage of distortion energy; forging the distorted metal bar in a radial direction through the afterheat, and quenching the distorted metal bar to obtain a radially-forged distorted blank of which solid fraction is more than 40%; re-melting the radially-forged distorted blank to obtain a semi-solid blank of the outer cylinder forged piece of the aircraft landing gear; finally performing semi-solid extrusion to obtain the outer cylinder forged piece of the aircraft landing gear. The process has characteristics of small required forming force, high material utilization rate and good mechanical properties of formed products.