Abstract: A rhodamine fluorescent probe (RP) was synthesized after three steps based on off-on mechanism using rhodamine 6G, vanillin and allyl chloride as raw materials. Its structure was characterized by NMR and FI-IR, and the photochemical properties and recognition performance were studied by ultraviolet and fluorescence spectroscopy. Effects of metal ion concentration were also investigated. The results indicate that the fluorescent intensity of the probe is weak, which increases after combination with Ag⁺. The fluorescent probe has exclusive Ag⁺recognition in ethanol/water (1/3, V/V) solution at 689 nm, which is less affected by metal ions such as Cu²⁺, Hg²⁺, Pb²⁺, Cr³⁺, Cd²⁺, Fe³⁺, Co²⁺, Bi³⁺, K⁺ and Na⁺. The fluorescent intensity of the probe has a linear relationship with Ag⁺concentration when the Ag⁺ concentration is in a range of 26.57~66.20 mmol·L^-1. (R²=0.9912). The Ag⁺detection limit of the probe is 16.09 mmol·L^-1. The job's plot confirms that Ag⁺and probe complexation ratio is 1:1 and the recognition mechanism is proposed.