Message Sequence Charts (MSCs) have been widely used in software engineering for system requirements and test speci‾cations. Since 2005, MSCs also have been adopted as the test speci‾cation of Test and Testing Control Notations-version 3(TTCN-3). We have developed and implemented the front-end part of graphical user-friendly en- vironment for the construction of MSCs test speci‾cations. The paper reports the technology of the part of our whole environment. It accepts test speci‾cations in TTCN-3 core-language and translates it into the graphical information. It also trans- lates graphical information into TTCN-3 core language. Therefore, the writing and generating of TTCN-3 speci‾cations can be e±cient with graphical mode.