In response to technical challenges such as multiprocess coupling during shield docking in high-pressure and high-permeability strata, high-pressure sealing, and steel shell concrete filling, a case study is conducted on the Jiangyin-Jingjiang Yangtze River Tunnel Project. A full-scale model test platform was designed and developed, and an innovative multistage progressive test method was constructed. This method sequentially connects five technologies in their construction sequence: shield shell drilling, segmented retreat grouting, leakage emergency handling, freezing wall thermal operation, and steel shell concrete filling. Over 30 progressive tests were completed, leading to the following conclusions: (1) The constructed multistage progressive test method is suitable for verifying shield docking under complex conditions. Utilizing the full-scale model test platform as its core carrier, this method accurately reproduces multifield coupling conditions such as 1.0 MPa high pressure, strong permeability, and low-temperature freezing. It provides a systematic and replicable test verification path for shield docking in complex strata. (2) The test quantified key technical parameters. A “four-point-one-line” positioning method was established for drilling, achieving a deviation of no more than 0.2° during small-angle drilling of the 80 mm-thick shield shell. Dual control and grade pressure control indicators were determined for grouting. The effectiveness of disposal measures for six types of risk scenarios was verified in leakage emergency treatment. Furthermore, measures such as optimized exhaust and compaction grouting were proposed to address issues of voiding and mold expansion in steel shell concrete. (3) The results were successfully applied to the shield docking of the Jiangyin-Jingjiang Yangtze River Tunnel. The engineering practice confirmed the reliability and universality of the proposed method, offering a valuable technical precedent for shield docking in high-pressure, strong permeability, and deep-buried conditions.