1. An apparatus of generating a multi-level test case from a unified modeling language (UML) sequence diagram (SD) based on a multiple condition control flow graph (MCCFG), the apparatus comprising: a UML SD metamodel storing unit storing a UML SD metamodel therein; an MCCFG metamodel storing unit storing an MCCFG metamodel; a model converting unit model-converting the UML SD according to the UML SD metamodel and the MCCFG metamodel to generate the MCCFG; and a coverage criteria unit converting the MCCFG into a plurality of test cases.