On-chip stimulated Brillouin scattering[SBS]has attracted extensive attention by introducing acousto-optic coupling inter-actions in all-optical signal processing systems.A series of chip-level applications such as Brillouin lasers,amplifiers,gyro-scopes,filters,and nonreciprocal devices are realized based on Brillouin acousto-optic interaction.Here,we first introduce the fundamental principle of SBS in integrated photonics and a method for calculating Brillouin gain;then we illustrate the Brillouin effect on different material platforms with diverse applications.Finally,we make a concise conclusion and offer prospects on the future developments of on-chip SBS.