The invention designs and synthesizes a novel supermolecular sensor P5-B1. Pillar [5] arene P5 is adopted as a subject, a pyridine functionalized naphthalene diformyl derivative B1 is adopted as an object, the subject and the object are complexed in a H2O-DMSO system, the object B1 penetrates into a molecular cavity of the object P5 so as to form the supermolecule P5-B1, the supermolecular sensor can be coordinated with Fe3+ to form a supermolecular sensor complex P5-B1Fe, and fluorescence quenching is carried out at the same time, so that supermolecular sensor can be applied in single selective fluorescent recognition of the Fe3+, and the lowest limit of detection is 5.01*10<-7>. F- is added in the sensor complex P5-B1Fe, and green fluorescence of the sensor complex is recovered, so that the F- can be efficiently selected and recognized, and the lowest limit of detection is 4.07*10<-6>. In addition, competitiveness distinguishing complex can be also used as an 'ON-OFF-ON' type fluorescence switch, and the recognition performance has important application value in the ion recognition field.