Liquid chromatography-mass spectrometry(LC-MS) combines the high separation efficiency of chromatography with the powerful structural determination of mass spectrometry, which not only enables more accurate analysis for the compounds, but also simplifies the pre-treatment of samples and makes the analysis more convenient. LC-MS, as an important tool for the qualitative and quantitative analysis of organic compounds, has been widely used in various fields such as pharmaceutical analysis, food and environmental monitoring, biological and medical research etc. As the key component of LC-MS, the role of the interface is to introduce and ionize the fractions from LC, and transfer the generated ions into the MS. Therefore, the improvement of ionization technology for the interface directly affects the advance and application of LC-MS. In order to obtain a higher sensitivity and a wider range of applicability, researchers have focused on the ionization technology to promote the desorption of chemicals, improve their ionization and transport efficiency, and reduce the interference of matrix effect. In this work, the development of traditional ionization technologies and the novel technologies reported for the interface of LC-MS in recent years are reviewed, including the ionization principle, interface construction, influencing factors, and the related applications. Their characteristics, advantages and disadvantages are discussed in details. Finally, the trend of ionization technology in development for the interface of LC-MS is prospected.