The advantages and disadvantages of both macro assembly language and high-level languages are analyzed, and the necessity of a general purpose software interface between them is explained. Then the differences among Compiled BASIC, FORTRAN, Pascal and C in procedure calls and data formats are dealt with. Finally, a method of designing a general purpose software interface between the 8086 macro assembly language and a number of high-level languges is introduced. This method makes it convenient to call the procedures from programs written in different languages.