Abstract: Photonic chips with powerful information processing capability are highly sought after. These are based on integrated photonics technology, wherein lithium niobate (LN), dubbed as the "silicon of photonics," is an excellent multifunctional crystal with comprehensive performance. The recent breakthrough using thin-film LN in overcoming the dense integration bottleneck of conventional LN based devices has provided a new avenue for integrated photonics, as well as a new platform for the research and application of nonlinear photonics, from which efficient all-optical on-chip processing may be expected in the near future. Here, we summarize recent important developments and explain how integrated nonlinear photonics based on thin-film LN will contribute to the future photonics revolution.