Abstract: Disinfection by-products (DBPs) widely exist in disinfected drinking water. There are still a large number of unknown DBPs in drinking water, which have potential toxicity and harms to human health. Currently, the identification of unknown DBPs is mainly performed by mass spectrometry, and the analysis method include targeted and non-targeted analysis. Targeted analysis shows excellent sensitivity for DBPs quantitative analysis, but has limited coverage for unknown DBPs. Non-targeted analysis offers a broad analytical scope, but its sensitivity is lower than that of targeted analysis, making it more suitable for the qualitative analysis of unknown DBPs. Based on the workflow of non-target analysis, this article reviews the research advances on non-target analysis for unknown DBPs in drinking water in the past five years from the aspects of sample pretreatment and different types of mass spectrometry, and discusses the role of non-target analysis for unknown DBPs in drinking water in the future.