Abstract: On the moon surface, the floating lunar dust will drop on the lunar rover under the influence of gravity, causing the degradation of the solar cells. Based on the layer overlapping theory, this paper establishes a model of the lunar dust attenuating the transmittance of light, in which the effects of the shape and the size of the particle are also analyzed. A comparative analysis shows that with this model and the NASA's model, we obtain the same variation tendency of the relative transmittance against the surface density of the lunar dust, as in an exponential function. On the other hand, with these two models, we see differences in the response of the relative transmittance value against the different lunar dust shapes, the characteristic sizes and the transmittance. The verification tests of scattering the simulated lunar dust on the solar cell are carried out in Beijing Institute of Spacecraft Environment Engineering using the facility for the lunar dust aggragations and absorption, and the results validate the model and show that it enjoys a better accuracy compared with the NASA's model.