Monitoring the structural transitions of individual molecules is of great significance because it helps to in depth explore the properties of molecules and provide diverse possibilities for molecular applications in the fields of chemistry,biology and material science.This review summarizes the strategy of using single-molecule electrical approaches to study molecular structure transitions at the single-molecule level in real time.Specifically,through the use of stable single-molecule devices for real-time electrical monitoring,the process of molecular structure transitions of a single molecule can be investigated,which helps to explore the nature of molecules in chemical and biological systems.In particular,the detection methods have been extended to the investigation of biological macromolecules for monitoring the conformational changes of nucleotide chains in different systems,such as double helix DNA,aptamer and DNA enzyme.In the end,we discuss the future challenges of probing structural transitions of single molecules,and provide prospects for further breakthroughs in this field.