Abstract: To meet the requirements of higher quality construction, the lining structure of circular hydraulic tunnels is shifting towards multi-layer lining superposition.However, there is currently a lack of accurate calculation models that can quantify the load distribution when the surrounding rock and multi-layer lining support are jointly considered.This article adopts the power series solution of plane elastic complex function theory and establishes a corresponding mechanical model based on the interaction relationship between surrounding rock and linings, which gives stress components at any position inside the surrounding rock and linings.The correctness of this model has been verified through boundary condition verification and comparison with numerical solutions.Subsequently, using the Pearl River Delta Water Resource Allocation Project as an example, this study conducted research and analysis to obtain the following main results:(1) Both radial and circumferential normal stresses in both surrounding rock and three-layer linings followed a cosine-like distribution with a period of π;(2) Among all layers in three-layer lining, lined steel pipe possessed relatively maximum elastic modulus, so it shared the highest bearing proportion;(3) Contact radial normal stress tended to decrease from outside to inside;(4) Different contact conditions resulted in different load-bearing patterns for laminated linings, for smooth contact, radial and tangential normal stress distributions were smoother, and stress distribution patterns at inner and outer boundaries within a same lining were opposite;(5) As hydraulic pressure inside multiplied, both the lining and surrounding rock exhibited radial compression, accompanied by circumferential expansion.These effects gradually diminished from the innermost layer towards the outer layers.The research findings elucidate the load transfer mechanism and principles governing the three-layer laminated lining structure of hydraulic tunnels under smooth contact, thereby offering a theoretical foundation for the designs and constructions of such lining engineering projects.