With the continuous development and progress of flexible electronic technology, the flexibility requirements are becoming more and more stringent for each device component. Polymer materials have been widely studied because of their good flexibility and dielectric properties. Polyurethane (PU) has a good research prospect in the application of different dielectric layers by virtue of its excellent functional tunability. This paper reviews the research status of PU as a dielectric layer in electronic devices. First of all, the common preparation methods of the polyurethane dielectric layer are briefly introduced. Then the advantages of PU and several existing modification methods of the PU dielectric layer are introduced. The application of PU as a dielectric layer in capacitive sensors and organic thin film transistors (OTFTs) is introduced and summarized in particular. Finally, we summarize the problems faced by the PU dielectric layer and the prospects for its future application. • Summary of polyurethane as dielectric for capacitive sensors • Summary of polyurethane as dielectric for organic thin film transistor • Summary of modification methods for dielectric properties of polyurethane