Small molecular weight substances are functional, as neurotrophic factors can be developed as therapeutic drugs to treat neurodegenerative disorder. Recently, a large number of natural and synthetic neuritogenic compounds have been discovered. These compounds have various structural features, including terpenoids, lipids, alkaloids, steroid glycosides, small molecular peptides, and so on. Some of them possess not only neurotrophic properties but also neuroprotective activities. The structure-activity relationships (SARs) and mechanism of action of some important compounds have been studied intensively. Increasing experimental evidence suggests that several of these compounds can be promising candidates for drug development.