本工作研究了在聚苯乙烯八乙基卟啉永久性光谱烧孔材料上进行光谱相位编码时域光全息读写中信息写入效率随激光谱带变宽而降低的现象，建立了分子转动引起光谱再分布模型，并计算了不同写入激光线宽下信号衍射效率随曝光量的变化规律，很好地符合了实验结果． In this work, we studied the phenomenon that the efficiency of information writing decreased as the laser band broadened in the phase-holographic optical holography reading and writing in the spectral phase encoding on the polystyrene octaethylporphyrin permanent spectral hole burning material. The molecular rotation Which caused the spectral redistribution model and calculated the variation law of the signal diffraction efficiency with the exposure under different write laser line widths, which accorded with the experimental results well.