Abstract: To implement functions of multi-language support in object-oriented language compiler automatic test tool (O-OCTT), the method of system functional extension is proposed. Based on the testing pattern and framework of O-OCTT, the design idea of plug-in is made use of. Test case generation is improved as a key part of the system, and the automatic generation of test case intergradation is used in the O-OCTT extension in order to achieve the function of multi-language support and meet the requirements of object-oriented language compiler automatic testing.