Hydrogen evolution from water electrolysis has become an important reaction for the green energy revolution. Traditional precious metals and their compounds are excellent catalysts for producing hydrogen; however, their high cost limits their large-scale practical application. Therefore, the development of affordable electrocatalysts to replace these precious metals is important. Transition metal phosphides (TMPs) have shown remarkable performance for hydrogen evolution and garnered considerable interest in the field of electrolysis. Based on the detailed introduction of TMPs in previous studies, we have systematically summarized the preparation methods, improvement methods, and development opportunities of TMPs and proposed “stimulatory factors” as a fundamental factor affecting the performance of TMPs herein. As the core of this research, “stimulatory factors” can provide numerous solutions to improve the performance of TMP materials and provide a good starting point for TMP research.