In this study, the effect of shikimic acid-rich aniseed extract on the color of heat-treated duck thigh by determining the color difference and myoglobin content. Meanwhile, the mechanism of action of aniseed shikimic acid on myoglobin in different mixing mass ratios was explored through fluorescence spectroscopy, thermogravimetric analysis, particle size measurement, and Fourier infrared spectroscopy. The results showed that the aniseed extract could improve the color of duck thigh to a certain extent. When shikimic acid mixed with myoglobin at a mass ratio of 1:10000 underwent heat treatment for 30 min, shikimic acid could fully bind to the iron porphyrin ring and tryptophan in myoglobin, and the surface particle size of myoglobin decreased from 756 to 183 nm. Compared with the blank group, the α-helix proportion of myoglobin increased by 14.55% in the treated group, and the proportion of random coil decreased from 46.61% to 31.63%. In conclusion, the addition of a proper amount of aniseed shikimic acid can effectively maintain the structural stability of myoglobin and improve the color of duck legs.