In order to reveal the source of the architectural norm embodied in the first built-form of ChongMyo's Main Building, three analytic types were introduced into research. According to the level of accepting the architectural form of ChongMyo in the Koryo Dynasty, these types were defined by 'newly interpreted form', 'newly introduced form', and 'coventionally accepted form'. Among the first built-form in ChongMyo's Main Building, the form of 'TaeSil' was newly interpreted on the basis of the Tang's realating norm, and the form of 'HyupSil' was newly introduced according to the contemporary trend that had increasingly regarded it as an indispensible form. But the form of 'IkSil' had the different source, that is, the architectural form of ChongMyo in the Koryo Dynasty. After reconstructed by the King ChungSun, that form had been sustained without any change until the end of Koryo Dynasty. In result, that form had been accepted conventionally at the first time of building ChongMyo in the ChoSon dynasty.