The invention provides a fluorescent probe. The molecular formula of the fluorescent probe is C86H84N6O12S4, and has the structural formula shown in a formula (I) as described in the specification, wherein t-Bu is tert-butyl. The fluorescent probe can simultaneously identify zinc ions, magnesium ions, cadmium ions and fluorine ions, has a detection limit of 4.71*10<-8>mol/L for the zinc ions, a detection limit of 1.56*10<-8>mol/L for the magnesium ions and a detection limit of 1.01*10<-8>mol/l for the cadmium ions, can realize a low-cost and high-flux test in a short time, is suitable for naked-eye qualitative detection and fluorescent quantitative detection of zinc ions, magnesium ions, cadmium ions and fluorine ions, and has a wide application prospect in the fields of biochemistry, analytical chemistry and environmental science. The invention further provides a preparation method and an application of the fluorescent probe.