Theoretical prediction models for anode current of Franck-Hertz experiment need to be established urgently. Existing related theoretical works focus on the analysis and interpretation of experimental results, while a small number of theoretical calculation and simulation works either fail to predict the theoretical curve comprehensively, or take too long time. Based on two lemmas and three hypotheses, this paper provides a comprehensive prediction of the theoretical curve within 1 second, and analyzes the reasons for its deviation from experimental results. After introducing corrections of trajectory and passing rate of electrons, we obtain the modified curve, which is highly consistent with the experimental result. Our results not only verify the correctness of Bohr's theory, but also can be applied to predicting the anode current of Franck-Hertz experiment within a certain range.