Abstract:In this study，the fruiting body，mycelium，and fermentation broth of Auricularia heimuer strain′1703′ were used as experimental material. The alkali dissolution acid precipitation method was utilized to extract melanin. The ultraviolet-visible spectroscopy（UV-Vis），Fourier transform infrared spectrometer（FTIR），scanning electron microscope（SEM）and high performance liquid chromatography（HPLC）were applied to study the structural characterization of melanin，the solubility，stability，and antioxidant activity of melanin in vitro were determined.The UV-Vis results showed that the maximum absorption wavelength of three melanins was 210 nm. The FTIR results showed that the three melanins had three characteristic absorption regions of natural melanin.The HPLC results showed that there was only one absorption peak for three melanins，and the retention time was basically the same. The results showed that the melanin from the three sources was easily soluble in an alkaline solution，slightly soluble in 75% ethanol solution，and insoluble in sterile water and most organic solvents. The stability results showed that the three melanins had good temperature stability and light stability. Fe3+ can promote the dissolution of melanin，and Fe2+and Cu2+ cause melanin instability.The results of in vitro antioxidant experiments showed that the three melanins had strong scavenging ability to DPPH，ABTS+，and OH free radical，among which the fermentation broth had the strongest melanin scavenging ability.