Considering the coexisting of electron resonant tunneling and miniband transport processes in a split-level energy system, and the effect of photogenerated carrier, we propose an optoelectronic transport theoretical model for the nanosilicon structure. We employ this model to calculate current density, electric field and electron density distribution under illumination, and the results show that resonant tunneling plays a major role in transporting the photogenerated electrons in a nanosilicon structure. Furthermore, we study the relationship between the photocurrent and the absorption coefficients, the applied bias, and the number of nanolayers. It is found that under certain conditions, hopping phenomenon occurs with photocurrent increasing, which is due to the redistribution of electric field inside the nanosilicon structure.