The Frank-Hertz experiment plays an important role in students’learning and understanding of quantum phenomena．Through theoretical derivation and experiments，the movement of electrons in F-H tube is studied，and the influence of reverse voltage and acceleration voltage on current intensity is analyzed on this basis．The influence of the first grid voltage on the electron energy is analyzed，and the effect of the grid voltage on the current intensity is studied through a large number of experiments，and the possible reasons for this phenomenon are proposed．This has certain inspiration for physics experiment teaching．