It was found that silver nanoparticles (AgNPs) could enhance co-luminescence effect of rare earths ions Tb3+ and Y3+. Based on this, a sensitive fluorescence detection method for the determination of dopamine (DA) was proposed. Moreover, the detection limit for DA was very low (down to nM). This is because DA can remarkably enhance the luminescence intensity of the Tb3+ ion by Y3+ in the colloidal solution of AgNPs, forming a new co-luminescence system. Furthermore, based on the metal enhanced fluorescence (MEF), AgNPs can sensitize the co-luminescence effect of the complex of Tb3+–Y3+–DA. In a neutral buffer solution (pH 7.50), the luminescence intensity of the system was linearly related to the concentration of DA in the range of 2.0–100nM, with a limit of detection as low as 0.57nM. The proposed method was applied for the determination of DA in dopamine hydrochloride injections and human serum samples with good accuracy and satisfactory recovery.