Chen Heqin believes that "children like painting, not because they have a natural impulse inside, but because they are stimulated by external things and left a deep impression in his mind, so he uses painting to express it." Chen Heqin's point of view is fundamentally correct. Because psychology is the reflection of the human brain on external things, without the stimulation of external things, there will be no content of psychological activities. The stimulation of external things is the origin of children's painting.