In order to study how the multireflection effects the spectral performance of the glimmer 1/4 wave plate,we deduce the Jones matrix which contains the multireflection on the side surface and discuss the change of the retarders spectral performance before and after it is filmed. In testing ,we measure the spectral curve of the retarder and the transmission of the wave plate before and after it is filmed. The results show that the periodic oscillation of the retarder and the transmisson is obvious before it is filmed,and the interval of the oscillation peak is in accord with the theoretical analysis. But after the wave plate is filmed,the periodic oscillation is removed.