With the advancement of national large-scale engineering projects， the construction of deep-buried tunnels has increased significantly， posing challenges to lining structure design under high external water pressure. Existing hydrogeological test devices and methods for deep-buried tunnels exhibit multiple limitations. This paper introduces a stratified hydrogeological test device and methodology for deep-buried tunnels based on controllable pressure relief equipment. The device isolates the test section from hydraulic connections with upper and lower rock strata using packer plug， employs a controllable pressure relief device to reduce high groundwater pressure within the test section， and measures groundwater pressure recovery time and final stratified groundwater pressure through piezometers. By establishing a dynamic equilibrium relationship between the built-in air vessel gas， groundwater pressure， and total infiltrated water volume， the permeability coefficient of rock strata can be calculated， enabling hydrogeological testing under groundwater inflow conditions. This device and method feature operational simplicity， strong applicability， and low cost， and have been successfully applied in a large-scale water resources allocation project， providing reliable references for structural design and safe operation of deep-buried tunnels.