We present our studies of recombination processes of H2+, HD+ and D2+ with high-energy electrons based on a time-dependent wave packet dynamics method. The final vibrational distributions of the products (H2, HD and D2) have been studied. The isotope effects of the final vibrational distributions and their dependence on initial states are elucidated. The study of the final vibrational distributions is relevant to the infrared gas laser researches.