To establish a lower cost, rapid, higher sensitive and specifical detection method for Ag⁺, we designed a novel probe containing the aptamer region and the complementary region of molecular beacon (MBs). In the absence of target, the fluorescence of FAM was quenched by BHQ. Upon adding the target, it would specifically bind to the aptamer, leading to the complementary region being recognized by MBs. MBs were cleaved when the EXO Ⅲ was introduced, which can release Ag⁺/DNA complex for the next round of reaction and free FAM for signal amplification,simultaneously. Hence, the amount of targets were quantified by fluorescence changes. Meanwhile, the performance of this method in real sample was also investigated to evaluate its sensitivity and selectivity. It showed that there was the optimal binding result between DNA probe and MBs when separating the molecular beacon from the complementary region with two bases, and it was achieved the best single-to-noise ratio (S/N) too. It had also a good linear range from 0.5 to 200nmol/L (R²=0.994), and a lower limit of detection of 0.1nmol/L. Importantly, a good linear relationship in the range of 20~200nmol/L (R²=0.998) was also obtained when this sensor was used for real sample analysis, moreover, it can distinguish 10nmol/L Ag⁺ from the mixed sample. The method for rapid detection of Ag⁺ has a good linear quantitative ability and operational performance, and its high sensitivity and specificity can meet the real demands.