In the cave age, humans began to decorate with murals reflecting daily life and cat hunting activities. Pictographic stone carvings in ancient Egyptian temples, carved beams and painted buildings in China's wooden buildings, and mirror-sticking, gold-inlaying and shellfish popular in Europe in the18th century all meet people's visual needs. Since the 20th century, with the development of structural technology, the internal space of buildings has been expanding and the use functions have become increasingly complex. The interior of the building needs not only beautification, but also scientific division to fully meet people's behavioral, physiological and psychological needs. For nearly half a century, interior design has gradually formed a branch of architectural design.

Interior design is based on people's behavior in indoor space. The plane layout should be arranged according to the use requirements of the space and the behavior mode of people in the space. The layout of residential buildings varies with the composition, age, culture, customs and hobbies of users. Public buildings also depend on management, people flow activities, social psychology and usage methods.

The richness of space is one of the main characteristics that distinguish architecture from other art forms. People are in a state of being "enveloped" in the internal space of buildings, so the proportion and scale of space and the relationship between people and the outside world have great influence on people's psychology. The hall of the medieval Gothic Cathedral has a small span, but its height and depth are great, and its towering volume creates a strong religious solemn atmosphere.

The proportion and scale of modern indoor space often consider the intimate relationship with people. The proportion and scale of space are often changed by raising or lowering the ceiling and the ground, or by using partitions, furniture, greening and water surface to meet different functional needs, or organized into an open, closed and intermittent space form, and different environmental atmosphere and psychological effects can be obtained through the harmony or contrast of color, light and texture.