Abstract: The research works of the theoretical physicists and experimental physicists are not synchronous and not seamless. In 1920s，before the hypothesis of de Broglie wave，Davisson and Kunsman had done the diffraction experiment of electron. Franck was one of the people who first knew the meaning of the experiment. Elsasser，one of Franck’s students，grasped it himself，and he wanted to do further experiment research，but did not get any result. He seeked help from Franck，but also failed. Elsasser published a note paper，presented that we could got the pictures of electrons diffraction when electrons go through crystals. Two years later，Born in a report in Oxford mentioned the paper of Elsasser again. Born’s words attracted the attention of Davisson and G.Thomson. Quickly they got good result and won the Nobel Price in 1937. Franck did not value the idea of Elsasser and made him lost a good chance to be one of the Nobel Price winners.

Key words: W. Elsasser, de Broglie wave, James Franck, Max Born