Diffraction characteristics of polycarbonate (PC)layers of recordable optical discs are investigated

by photoelectric detection technique. The results such as diffraction spectrum range，distribution of diffracted light intensity，spectral overlap，free spectral range，relationship between angles and wavelength，angular resolution and grating constant are analyzed，respectively. The experimental results are consistent with the diffraction theory. The method makes up the shortage of traditional grating experiments and it is helpful to improve undergraduates' recognitions on diffraction grating in the college optics.