It is crucial to acquire the jamming thresholds of the photoelectric devices in charge coupled device (CCD) image sensing applications by nonexperimental means, which is a unique way to obtain the thresholds sometimes. Affecting factors of pixel saturation and crosstalk effects in interline transfer CCD are analyzed briefly. The intrinsic relationship and difference between vertical smear, blooming and crosstalk are studied. Results preliminarily suggest that crosstalk is not sensitive to the fractional amount of smear. An extrapolation method to estimate thresholds of the pixel saturation and crosstalk column saturation effects with image sensor specification and historical data of laser irradiation effects is proposed. Device parameters such as quantity of saturation signal charge, pixel size, quantum efficiency and blooming suppression are used in the estimation. Laser irradiating experiments are carried out to measure the jamming thresholds of two similar Kodak area CCDs. The deviations between the estimation results and the experimental data are 3% and 2%, respectively. The acceptable deviations indicate that the predicting method is feasible.