A method for reading NC files for the interface based on C # and Matlab mixed programming is introduced. The Matlab toolbox library of NC files is used to write Mfile for the corresponding method, and then the Mfile is compiled into a DLL class library, and the DLL library is called in order to achieve the overall function, using C# as the development platform for the interface. An case of the WebService interface is written to extract any point or free clipping of NC files. The feasibility of this method is verified while the interface can be quickly called.