Kerogen in oil shale plays a crucial part in the shale oil and gas generation. Here, photoconductive measurement was used to evaluate the decomposition process of Huadian oil shale. The photoconductivity of the semi-coke is a clear indicator of different pyrolysis stages, including moisture evaporation, primary pyrolysis of kerogen, decomposition of asphalt monomer, and mineral decomposition. Furthermore, the distribution model of electrical resistance (R) and photoconductance (ΔI) for Huadian oil shale is plotted, indicating an inverse proportion between R and ΔI. We believe that the photoconductive measurement will be a valuable means for the nondestructive characterization of oil shale pyrolysis, which is helpful to optimize the comprehensive utilization of this unconventional resource.