Abstract: The precondition of solving life prediction and life extension for airplane structures is to work out a typical load-time history, i.e. load-spectrum, which can simulate airplane's real service situation. This is the basis of theory analysis and whole-size structure fatigue test. In view of this, the data treatment and the compilation procedure of median stochastic load-spectrum are discussed. The data treatment expert system for median stochastic load-spectrum is created. It includes system framework design, data description and parameter configuration, implementation process and database design, etc. The research achievement has been used for load-spectrum data treatment and compilation for airplane, aeroengine, airplane landing gear and main fighting tank, etc.