This paper introduces how to design the software of EMC test based on object-oriented programming idea. According to main functions, this software is divided into five objects, which are test template object, instrument object, apparatus object, graph object, and report object. Test template object is the core of this software, and information of test item, frequency band, test procedure and parameters of instruments are included. Instrument object encapsulates VISA instructions of remote instrument. Apparatus object encapsulates transfer coefficient which corrects test data. Graph object and report object build data diagram and report according to test data. Software of EMC test realizes automation of test procedure and improves test efficiency.