Nowadays, when the country vigorously promotes "high-quality development", the requirements of laboratory environment in various disciplines in universities are gradually improving. In the context of "reducing the development" of Beijing’s overall planning policy, the utilization of campus underground space has become one of the indispensable means for the development of universities in Beijing in recent years. Meanwhile, the strong anti-interference of the underground laboratory also shows important advantages. By investigating and analyzing the existing literature of cases of campus underground experimental space at home and abroad, several design principles of underground experimental buildings are summarized. On this basis, combined with the current situation of the location and the function of the peripheral existing buildings, planning and design on the surrounding underground space of the observatory, located in the western part of Tsinghua University campus has been done. Different schemes for the ground entrance form, plane function and streamline organization logic have also been compared, which is hoped to provide reference for the future development of the campus underground experimental space in Tsinghua University.