The invention belongs to the biology technical field and relates to an inducer promoting an embryonic stem cell to be differentiated into a nerve cell, a molecular structure of the inducer, a method for inducing the embryonic stem cell to be the nerve cell by taking the inducer as the medicine compound and application for treating the Alzheimer disease by implanting a neural stem cell obtained by the differentiation of the inducer into an animal brain pattern. After the animal experiment, from the positive and negative aspects, the result demonstrates that the inducer can play a role of promoting the phosphorylation of ERK, and the neural stem cell obtained by induction and differentiation can be implanted into the brain of a mouse pattern with the Alzheimer disease, so as to obviously improve the learning and memory functions of the mouse pattern. The compound can be further used for preparing a medicine for promoting the embryonic stem cell to be induced and differentiated into the nerve cell, and the neural stem cell obtained by the induction and the differentiation can be used for preparing the medicine for treating the Alzheimer disease.