本文提出了一个带悬键和饱和键的Bethe格子模型,计算了非晶态硅的带隙态密度,证明了Spear实验的带隙态Ex峰是由悬键产生的,E_y峰是由饱和键产生的.还得出了:当饱和原子改变时,Ex峰保持不变,Ey峰位置随饱和原子与Si原子键的能量差而变化,能量差越小,Ey峰与Ex峰的间距越大,峰的强度也随之改变. In this paper, a Bethe lattice model with dangling bond and saturated bond is proposed, and the bandgap density of amorphous silicon is calculated. It is proved that the Ex peak of the bandgap of Spear experiment is generated by dangling bond, and the E_y peak is composed of saturated bond The results also show that when the saturated atoms change, the Ex peak remains unchanged and the Ey peak position changes with the energy difference between the saturated atoms and the Si atoms. The smaller the energy difference, the larger the distance between the Ey peak and the Ex peak , The intensity of the peak also changes.