The structural color and microstructure of nacre in bivalve shells of Pinctada maxima were investigated by optical reflection spectra, scanning electron microscopy and theoretical simulation. The following results are obtained: (1)The thickness of aragonite tablets decreased significantly from growing to central region of nacre, which leads to a blue-shift of reflection peak wavelength with the same reflection order obviously; (2)The structural color of nacre in bivalve shells of Pinctada maxima is derived from the combination effects of aragonite-protein multilayer structure and yellow pigments in nacre.