This study is concerned with the process of development and architectural characteristics of secular stained glass in the 20th century. Stained glass had been architectural art from the origin. But it had declined since the Renaissance era, and began to revive in the early 20th century. Stained glass work is very flourish in Korea today, but it is still treated as simple decoration or 2-dimensional mosaic. Architect and interior designer even have little understanding of architectural character of stained glass. In order to recover the architectural nature of stained glass, I have considered the process of development of secular stained glass in the 20th century, and analysed the works of Frank Lloyd Wright, the postwar German artists, Georg Meistermann, Ludwig Schaffrath, Johannes Schreiter, and English artist, Brian Clarke. Major findings of the study are as followings : First, stained glass has come to life again from the secular glass painting decoration in the end of the 19th century, through Art-Nouveau, De Stil, Bauhaus in the beginning of the 20th century, and L'Art $Sacr\acute{e}$. Second, Frank Lloyd Wright, the postwar German artists and Brian Clarke have established the architectural concept and potentiality of the modem stained glass in the secular field. Third, They have done by coming back to the basic creative method by traditional lead-came technique in spite of the development of various materials and techniques. Forth, stained glass fundamentally has architectural characteristics as the characters of Space, Time, Place, Context, and they have showed the new possibility of stained glass by recovery of these characters.