Abstract: Considering that there is no reference experience in China regarding tunnelling in very thick self-weight collapsible loess, and based on international research of collapsible loess treatment methods and the features of such construction, this paper discusses the limitations of the GB50025-2004 Code for Building Construction in Collapsible Loess Regions as applied in metro tunnel construction; proposes relevant treatment principles and analysis processes for tunnel construction in collapsible loess and researches the corresponding construction schemes by using a metro tunnel in very thick self-weight collapsible loess in Xi’an as an example. Based on the given treatment principles, analysis processes and surrounding environment condition, it is determined that adopting the preferred principle of “alignment bypassing” is an economic and highly feasible method when such a complex tunnel project (including open-cut tunnelling, shallow bored tunnelling and shield tunnelling) will pass through a very thick self-weight collapsible loess stratum. Additionally, the paper also provides some valuable suggestions for treatments and control measures in this context.