The shrouded blades are widely utilized in significant rotating equipment such as aircraft engines due to their functions of enhancing blade stiffness and reducing secondary losses. And the multi-channel high-precision online monitoring of blade tip clearance parameters is a crucial aspect in ensuring the safety and efficiency of engine operation during its runtime. To achieve this goal and inhibit the adverse effects of the axial displacement, a novel "I-shaped" core-pole capacitance sensor is designed in this paper. Based on the modified labyrinth teeth, a tip clearance measurement model is established using the parallel-plate capacitor principle. A 12-channel blade tip clearance measurement system based on I-shaped core-pole sensor was developed. Calibration within a 3 mm measurement range was conducted on a simulated labyrinth disc, and precision testing was performed under ±1 mm axial displacement. The results indicate that the measurement accuracy of the aforementioned blade tip clearance measurement system exceeds 45.4 μm. The final stage involved the synchronization testing platform for blade tip clearance of actual engine blades with shrouds, encompassing twelve measurement points across three levels. Results demonstrate that the proposed 12-channel blade tip clearance measurement system exhibits high reliability and repeatability, and meets the needs of tip clearance measurement of shrouded blades.