The base is located at the exit of the expressway in the west of Hangzhou. It is an important location at the gateway to the west of the city. In a narrow and long site of 150mx40m, with viaducts in the south and high-rise residential areas in the north, we carried out extreme operations through the step-by-step setback of the building volume. It actively responds to the city entrance portal form and handles the urban interface relationship, creates an interesting office space at the same time.