Asmartphone-assisted portable dual-mode immunoassay was constructedbased on curcumin nanoparticles (CNPs) and carbon dots (CDs) for gentamicin (GEN) detection. CNPs were labeled with goat anti-mouse IgG (Ab2) to create a conjugation that coupled dual signals to concentrations of GEN antigens. CNPs were introduced to pH 7.4 water and showed insignificant color and optical responses. When exposed to the high pH environment, the structure of CNPs changed and color and optical propertieswere restored. Because of the inner filter effect (IFE) between CNPs and CDs, the fluorescence of CNPs at 550nm quenched the fluorescence of CDs at 450nm. Colorimetry and ratiometric fluorescence (F550 nm/F450 nm) dual-mode immunoassay linearly correlated with GEN ranged from 10-4 to 100µg/mL with a detection limit (LOD) of 8.98 × 10-5µg/mL and 4.66 × 10-5µg/mL, respectively. This work supplied a portable, sensitive, and specific platform to detect GEN.