Color-coding analysis from chemicals of concern is in great demand, but faces low sensitivity and specificity, low resolution, and complex processing among the many challenges. Here, this work resolves these issues to enable the elusive quantitative detection of a variety of fluoroquinolone (FQ) antibiotics. A fluorescent sensor based on the dual-emitting lanthanide metal-organic frameworks combining Tb3+ and Eu3+ as the luminescent center and 1,3,5-benzenetricarboxylic acid as the ligand is constructed. Due to the different sensitization effects to lanthanide metals and different inherent fluorescence emissions of FQs, the sensor exhibits characteristic color variations towards nine FQ and enables the discriminative detection of multiple antibiotics with self-calibrated signals. For the first time, a polynomial surface fitting process is developed to correlate the coordinates of color-coding map and target concentration for quantitative analysis. Moreover, a smartphone-enabled sensing system is demonstrated for on-site imaging analysis of antibiotics. The demonstrated innovative antibiotic detection and color-coding-based signal processing approach will inform the development of cutting-edge analysis systems for public health and environmental monitoring.