It is an interior design case for a spa house with an indoor area of 1,500 square meters. It is located in the downtown of the city with numerous competitors, a noisy environment, and no natural landscape. The designer believes that the core value of space design for a commercial project is to help owners improve their business competitiveness by creating a space environment that in line with their business and leaves a unique impression on customers. The designer builds a zen ‘cave space’ to resonate with cave Time psychology and let the customer obtain a distinctive service experience.