Carrier behavior in CuInS2 thin films on the and microsecond time scales is discussed in detail. The transient absorption data shows that the photo-generated carriers rapidly relax accompanied by energy change. The photo-generated charge carriers are extracted by a bias electric field (E) in the nanosecond transient system; moreover, E would improve the efficiency of photon conversion to charge carriers and enhance the velocity of extracted charge carriers. In addition, there is a threshold of illumination intensity in the extraction process of charge carriers in the CuInS2 thin film. There is carrier recombination if the illumination is higher than the threshold. The corresponding loss further increases with illumination intensity, and the recombination percentage is almost independent of E. The results are useful to further understand the characteristics of carriers in the CuInS2 thin film and are important for the operation of the corresponding devices.