Coil-type magnetic flux detection technology has been widely used in clinical diagnosis applications. However, adjacent magnetic samples’ detection signals are prone to aliasing. Most of the existing researches used algorithm processing and sample space isolation to avoid the mutual interference of signals, which limits the development of this technology in the field of point-of-care testing. In view of the above problems, this study uses mathematical physical modeling combined with finite element simulation to analyze the structure of the coil-type magnetic flux sensor, and optimizes the sensor structure. The final experimental results show that the optimized sensor can effectively distinguish the adjacent magnetic signal sources with a distance of 4 mm. In the immunochromatographic quantitative detection of gastrin-17 in clinical samples, the detection range reached 11 pg / mL ~ 110 ng / mL. The above result confirm that the optimized sensor structure has the capability of multiplex synchronous multiplexing detection.