Boulder is a difficult geological problem commonly encountered in shallow tunneling. Conventional boulder treatment methods, such as hand breaking by steel rods, blasting and expanding by cement expanding agents, have obvious shortcomings. Therefore, a new boulder treatment technology, i.e., hydraulic splitting technology, is presented in this paper. The composition, working principle, construction techniques of hydraulic splitters, as well as the comparison between the hydraulic splitting method and the conventional methods, are discussed. The paper can provide reference for similar projects in the future.