Industrial and interior designer, Karim Rashid, uses curves and colors and applied techniques which he used in product design on plastic materials, acrylic, and tinted glass. As plastic materials are easy to shape, he uses them as major roles along with acrylic, tinted glass, traditional building materials, tiles, cement, and paint externally and internally in Semiramis hotel Athens, Greece, and Prizeotel hotel, Hamburg. He demonstrates the innovative use of the modern petrochemical materials, matching plastic materials, acrylic, and tinted glass on building structure externally and internally. Through the use of plastic materials, acrylic, and tinted glass, different degrees of opaque, translucency, and transparency can be expressed. Colors on plastic materials can have changes of brightness, chroma, and hue to create space emptiness or abundance. Karim Rashid's design rooted in the concept of ＂democratic design＂ originated from Scandinavian countries. Based on democratic design, he fuses industrial products with hotel installation art and furniture. Choosing Greek and German traditional cultural colors as base colors, he reinterprets Greek and German colors. The overall color representation in Semiramis hotel, Athens, as Karim Rashid said, shows positive energy, young atmosphere and hospitality. These qualities provide an alternative attraction in comparison with traditional hotels. As for Prizeotel hotel, Hamburg, as the official website states, visitors can ＂experience colors and shapes of 'Designocracy'.＂ This research uses five major elements of democratic design to discuss and analyze Karim Rashid's color expression techniques through the use of plastic products, acrylic, and tinted glass. Through analyzing the expressive design techniques of Semiramis hotel, Athens, and Prizeotel hotel, Hamburg, color design guidelines and purposes of the two cases can be categorized. The categorized expressive color design schemes and the linking of color cognition adjectives of the two hotel cases are also studied.