Morphing aircraft of telescoping wing can change wing area and aspect ratio by a variable-span morphing wing ,also change wing configuration and aerodynamic characteristics,which accommodate multiple flight conditions. This paper introduces in brief the development history of morphing aircraft of telescoping wing,and mainly explores the aerodynamic characteristics of a supersonic air vehicle with the concept of telescoping wing．The results of the analysis demonstrate an improvement in the aerodynamic characteristics of the morphing aircraft of telescoping wing．Wing span extension in subsonic represents a increase in aspect ratio and enhance the lift-drag ratio,in the form of a reduction in the induced drag,resulting in an increase in range．The wing span contraction represents a reduction in the aspect ratio and cut down the wave drag in supersonic,resulting in an increase in lift-drag ratio and improvement of flight performance of supersonic．Telescopic wing can take good consideration of both subsonic cruise and supersonic speed in supersonic aircraft design.