In the 1970's the Interior Design Associations was established and the activity of youth designers who werecalled the "first generation of Korean interior designers" were created. This study is aimed to analyze characteristics and trends of commercial interior design in the 1970's. The design methods include the documentary research and the actual proof research conducted. The frames of analysis were made by the background theories about Korean interior design, and the annual case studies were analyzed and estimated according to the design types. The design types were analyzed by the geometrical simplicity research, the romantic emotional expression, the Korean identity expression, the machine technical asthetic expression and the eclectic style with western classics. In the early 1970's, the abstract, brief, and simple expression were presented most frequently by the geometrical form and the repetition of the pattern. From the mid-1970's the romantic and emotional atmosphere of the youth culture that was popular at that time were expressed as vernacular design by the rough finishing of the natural materials such as plaster, brick, and wood floorings etc. The space such as a Korean food restaurant relates to the Korean traditional culture aims to be different through the expression by the Korean traditional patterns, furniture, and materials. In the late 1970's the metals and glass were used for the expression of the machine aesthetic form but was not popular because of the rare application. The type that revived the past western traditional form was presented by using the arch, dome, and the curved and luxurious moldings.