A hybrid molecularly imprinted ratiometric fluorescence probe was constructed based on the characteristic that dicamba (DIC) can brighten the blue fluorescence of Eu-MOFs. According to the change of the fluorescence color of the probe solution from yellow to blue, a smartphone-assisted detection platform was established to realize the visual detection of DIC. The detection limits of fluorescence and smartphone analysis are 0.08 μM and 0.27 μM, respectively. The sensing mechanism study shows that the reaction belongs to the cross-linking fluorescence enhancement effect. Eu-MOFs form hydrogen bonds with the carboxyl groups of DIC and form a dendritic network structure, which inhibits the non-radiative transition of the luminescent center and improves the charge transfer efficiency to achieve enhanced fluorescence. So, this work provides a method for the fluorescence quantitative detection and on-site visual detection of DIC by smartphone in Hordeum vulgare and Setaria italica.