In this paper, a series of Cs3Cu2I5 perovskite phosphors modified with L-histidine (L-His) and 5-aminovaleric (5-Ava) acid were prepared by simple room temperature ball milling method. The phase, morphology, optical and stability properties of Cs3Cu2I5∶x%L-His and Cs3Cu2I5∶x%5-Ava(x=0, 0.5, 1, 1.5, 2) perovskites were analyzed. The presence of amino acids does not change the crystal structure of Cs3Cu2I5perovskite, which still belongs to the Pnma space group. However, the introduction of amino acids affects the grain size of perovskite and effectively improves its optoelectronic properties. When x=1, the fluorescence intensity of Cs3Cu2I5 perovskite modified with L-His and 5-Ava increases by about 1.30 and 1.41 times compared with that of pure Cs3Cu2I5 perovskite, and the photoluminescence quantum yield (PLQY) increases by 25.09 percentage points and 30.47 percentage points, respectively. The fluorescence lifetime of the modified perovskites is effectively prolonged. It is found that the improvement in performance may be related to the function of amino and carboxyl groups in amino acids, which blunts the defects of perovskites and inhibits energy loss in non-radiative recombination processes. In addition, the blue light-emitting diode (LED) was prepared by Cs3Cu2I5 perovskite phosphor modified with L-His and 5-Ava acid, and the respective light efficiency is 1.85 and 2.10 times higher than that of pure Cs3Cu2I5 device under biased current of 70 mA, indicating that such materials have great application value in the LED field.