Abstract: OBJECTIVE To identify the structure of related substances of ivabradine tablets and to provide basis for process optimization and quality control. METHODS Ultra high performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry(UHPLC-Q-Orbitrap HRMS) was used to detect related substances of ivabradine tablets and their forced degradation solution. According to its precise molecular weight, fragmentation law and chemical structure to infer the structure of related substances. RESULTS A total of 22 related substances were discovered, their possible chemical structures were identified, and their sources were assigned. CONCLUSION UHPLC-Q-Orbitrap HRMS technology can effectively identify related substances of ivabradine, which is of great significance for its optimization of production process and quality control.